The History of a Mouthful of Bread
by
Jean Mace
Part 4 out of 6
for it cannot be seen any more than the air which fills an empty glass.
But I can tell you where there is some, and you even probably know it by
its effects, although you have never heard its name.
Do you remember, on your aunt's wedding-day, that there was a sparkling
wine called champagne, at the grand breakfast? You smile, so I conclude
somebody gave you a little to taste; and if so, you will remember how
sharp it felt to your tongue. Do you remember, too, how the cork flew
out when they were opening the bottle, and how the noise of the "pop!"
startled more little girls than one? It was _carbonic acid_ which
sent the cork flying in that wild way; the carbonic acid which was
imprisoned in the bottle, in desperately close quarters with the wine,
and which accordingly flew out, like a regular goblin, the moment the
iron wire which held down the cork was removed. What sparkled in the
glass, making that pretty white froth which phizzed so gently, as if
inviting you to drink, was the carbonic acid in the wine, making its
escape in thousands of tiny bubbles. What felt so sharp to your tongue
was the same carbonic acid, in its quality of acidity, for thence it
has its name; the word _acid_ being borrowed from a Latin word
signifying the sharp pungent taste, almost _fine-pointed_ as it
were, peculiar to all substances which we call _acids_.
It is carbonic acid also which causes the froth in beer and in new
wine when bottled. It is he who makes soda-water sparkle and sting the
tongue, and ginger-beer the same, if you happen to like it; and so far
you have no particular reason for thinking ill of him. But beware. It
is with him as with a good many others who have sparkling spirits, who
make conversation effervesce with gayety, and who are very seductive
in society when you have nothing else to do but to laugh over your
glass, but whose society is fatal to the soul which delivers itself
up to them. This charming carbonic acid is a mortal poison to any one
who allows it to get into his lungs.
You remember what a violent headache your servant suffered from the
other day after ironing all those clothes you had in the wash? She
owed that headache entirely to this work which she did for you. She
had remained too long standing over the coals over which her flat-irons
were being heated. You know already that when charcoal burns, it is
from the carbon uniting with the oxygen of the air; from this union
proceeds that mischievous child, carbonic acid gas, in torrents, and
the poor girl was ill, because she had breathed more of this than was
good for her health. Observe well, that the room-door was open to let
in the fresh air, and that there was a chimney, to allow the carbonic
acid to escape. It was on this account that she got off with only a
headache. Unhappily, there have sometimes been miserable people who,
weary of life, and knowing this, but not knowing or thinking about the
God who overrules every sorrow for good, have shut themselves up in
a room with a brazier of burning charcoal, after taking the fatal
precaution of stopping up every opening by which air could possibly
get in; and when at last, in such a case, uneasy friends have forced
open the well-closed door, they have found nothing within but a corpse.
Then, too, there are those frightful accidents of which we hear so
often, of workmen groping their way down into long disused wells, who
have died as they reached the bottom; or of sudden deaths in coal-pits.
In general these have been owing to the poor victims encountering the
long pent-up carbonic acid gas, whose poisonous breath blasted and
destroyed them at once.
You may well ask why I am telling you such horrible stories, and what
I am coming to with my carbonic acid? But you have more to do with it
than you think, dear child. You, and I, and everybody we meet, nay,
and the very animals themselves, since their machines are of the same
sort as ours, are all little manufactories of carbonic acid. The thing
is quite clear. Since there is a charcoal fire lit in every part of
our body, there always arises from the union of the oxygen brought by
the blood with the carbon it meets in our organs, that mischievous
child we have been talking about; and our throat is the chimney by
which he gets away. He would kill us outright were he to stop in the
house.
This is how it comes about: In proportion as the blood loses its oxygen,
it picks up in exchange the carbonic acid produced by combustion, so
that it is quite loaded with it by the time it returns to the lungs.
There it takes in a fresh supply of oxygen, and discharges at the same
time its overplus of carbonic acid, which is driven out of the body
by the contractions of the chest, pell-mell with the air which has
just been made use of in breathing. You are aware that this air is not
the same at its exit as at its entrance to the body, and that if you
try and breathe it over again it will no longer be of the same use to
you. That is because it has lost part of its oxygen and brings back
to you the carbonic acid which it had just carried off. If you take
it in a third time, it will be still worse for you; and in case you
should continue to persist--the oxygen always diminishing, and the
carbonic acid always increasing in quantity--the air which was at first
the means of your life will at last become the cause of your death.
Try, as an experiment, to shut yourself up in a small trunk, where no
fresh air can get in; or even in a narrow closely-shut closet, and you
will soon tell me strange news. There will be no occasion to light a
charcoal fire for you in there. Enough is kept burning in your own
little stove, and you will poison yourself.
You see now that the dreadful stories I was telling a short time ago
have something to do with you, and that it is a good thing to be warned
beforehand. And now tell me, when a hundred people--or I ought to say,
a hundred manufactories of carbonic acid--are crowded together for a
whole evening, sometimes for a whole night, in a space just big enough
to allow them to go in and come out; tell me, I say, if that is a sort
of thing which can be beneficial to the health of little girls whose
blood flows so fast, and who require so much oxygen; and whether, on
the contrary, it is not one's duty to keep them away from such scenes?
There may be amusement there, I know; but the best pleasures are those
for which one does not pay too dearly. I have seen the very wax lights
faint and turn pale all at once, in the very midst of those murderous
assemblies, as if to warn the imprudent guests that there was only
just time to open the windows.
And this reminds me of a point I had nearly forgotten. Wax-candles arc
like ourselves. In order to burn, they must have oxygen, and, like us,
they are extinguished by carbonic acid. But like us also--and indeed
to a greater extent, because they consume much more charcoal at
once--they manufacture carbonic acid. Hence that very illumination
which affords the company so much pleasure and pride is plainly an
additional cause of danger. Each of those wax-lights which is spread
around with such a prodigal hand, the only fear being that there may
not be enough of them, is a hungry intruder employed in devouring with
all his might the scanty amount of oxygen provided for the consumption
of the guests.
From each of those cheerful flames--the suns, as it were, of the festive
assembly--shoots out a strong jet of carbonic acid, contributing by
so much to swell out the already formidable streams of poisoned gas,
exhaled to the utmost extent by the dancers. And wait--there is still
something else I was forgetting. You dance. And I told you last time
at what cost you have to dance. You have to make the fire burn much
quicker than usual, that is, to consume a great deal more oxygen at
once, and so you double and treble the activity of the carbonic acid
manufacture: and this just at the moment when it would be so convenient
that it should go on as slowly as possible! After this, you need not
be surprised that people should look fagged and exhausted next morning.
What astonishes me is that they are not obliged to lie in bed
altogether, after treating their poor lungs to such an entertainment.
And even if you have spared your legs, you are not much better off,
as you are sure to find out in time, especially if the thing is repeated
too often.
When I told you just now that the dance of labor was worth as much as
the dance of the ball-room, was I right or wrong? What do you say
yourself?
I could repeat the same of theatres--places of entertainment specially
adapted for impoverishing the blood, and ruining the health of the
happy mortals who go there, evening after evening, to purchase at the
door the right of filling their lungs with carbonic acid, not to speak
of other poisons. You must see clearly that such places as those are
not fit for little lungs as dainty as yours; and this may help you to
submit with a good grace when you see people going there without you.
Grown-up people escape moreover, because the human machine possesses
a strange elasticity, which enables it to accommodate itself--one
scarcely knows how--to the sometimes very critical positions in which
its lords and masters place it without a thought. But to do this, it
is well that it should be thoroughly formed and established; for you
run a risk of injuring it for ever, if you misuse it too early in life.
Tell this to your dear schoolboy brother, when he wants to smoke his
cigar like a man. If his lungs could speak, they would call out to him
that it was very hard upon them, at their age, to be so treated, and
that he ought at any rate to wait till they had passed their
examinations!
But I must not get into a dispute with so important an individual, by
throwing stones into a garden which is not under my care. For you, my
dear child, the moral of this day's lesson--which to my mind is much
more alarming than a hobgoblin tale, since it concerns the realities
of every-day life--is clear; and it is this:
Seek your amusements as far as possible in the fresh air. In the summer,
when the lamp is lit, bid your mamma a sweet good-night, and go to
bed. In the winter do not wait till there is a great quantity of
carbonic acid in the room where the grown-up people are sitting, before
you retire to your own like a reasonable girl, anxious not to do
mischief to that valuable and indefatigable servant, the poor blood!
Not to mention that if she were to injure him too much, she would have
to bear his grumbling for the rest of her life. We cannot change him
as we change other servants.
LETTER XXVI.
ALIMENTS OF COMBUSTION.
We have spent a very long time, my dear child, over the little fire,
which goes on burning secretly in every one of us, quietly devouring
what little girls eat with such a good appetite, quite unsuspicious
of what they are doing it for. However, if I mean to finish the history
of our mouthful of bread, I must push on to its last chapter.
The _whole_ of what we eat is not burnt, as you may easily suppose; for,
if it were, what would the blood have left to feed the body with, and to
repair in due proportion the continual destruction or waste which goes
on in our organs? Our food, or "_aliments_" as the general collection of
different sorts of food is called, are divided into two very distinct
sets: some, which are destined to be burnt, and which are called
_aliments of combustion_; others, which are destined to nourish the
body, and which are called _aliments of nutrition_. I have to tell you
now about these last, and you will find their history by no means
uninteresting.
Learned men having detected, beyond the possibility of a doubt, the
existence of these two sorts of aliments, one is tempted to think they
ought to have made it known to the cooks, and that ever since so
important a discovery, the dishes on all well-regulated tables should
have been arranged accordingly; aliments of combustion on one side,
aliments of nutrition on the other. It cannot be enough merely to give
your guests a treat; you ought to provide them with everything necessary
for the proper fulfilment of the claims within; and if you give some
nothing but combustibles, leaving the others no share of fuel, how
will they be able to manage? Nobody thinks about this, however; not
even cooks, to begin with, who, as far as fire is concerned, find they
have had quite enough to do with it in their cooking; and as for the
guests, when they have had their dinner they go away satisfied, as a
matter of course, quite as well provided for as if the mistress of the
house had made her calculations, pen in hand, while writing out the
bill of fare, with a view to combustion and nutrition. Now, how is
that?
It is because the two sorts of aliments are, for the most part, met
with together in everything we eat, so that we swallow them at once
in one mouthful; and have therefore no need to trouble ourselves further
on the subject. There is our bit of bread, for instance. What is bread
made of? Of flour. Bread, then, must contain all that was previously
in the flour. Very good. Now I will teach you how to discover in flour
the aliment of combustion on the one hand, and the aliment of nutrition
on the other.
Take a handful of flour, and hold it under a small stream of water;
knead it lightly between your fingers. The water will be quite white
as it leaves it, carrying away with it a fine powder, which you could
easily collect if you were to let the water run into a vase, where the
powder would soon settle to the bottom. That powder is starch--the
same starch as washerwomen use for starching linen, and which our
grandfathers employed in powdering their wigs. You had some put on
your own hair one day when you were dressed up as a court-lady of olden
time. Now, starch is an excellent combustible. People have succeeded,
by means which I will not offer to detail here, in ascertaining almost
exactly what it is made of, and they have found in it three of our old
acquaintances, oxygen, hydrogen, and carbon, combined together in such
proportions that 100 ounces of starch contain as follows:
Ounces.
Carbon 45
Hydrogen 6
Oxygen 49
---
100
I give you the calculation in round numbers, so as not to burden your
memory with fractions; and I will do the same with the other sums I
shall have to go through to-day, this being, let me tell you, an
arithmetical day. Besides, I could scarcely take upon myself to warrant
the absolute correctness of those very precise fractions people
sometimes go into. Even our learned friends squabble now and then as
to which is right or wrong over the 100th part of a grain, more or
less, in making out their balance, and you and I will not offer to
decide between them. I always think we have accomplished wonders in
getting even _near_ the mark, and with their permission we will
stop there.
Starch, then, of whose weight carbon constitutes nearly one-half, is
of course a first-rate combustible. Indeed, one may almost consider
it the parent, as it were, of at least half our aliments of combustion,
for if (in consequence of a certain operation, which nature has the
power of performing for herself, in certain circumstances) it loses
a portion of its carbon, so that there remain but 36 ounces of it in
the 100 of starch, our starch is turned into something else; now can
you guess what that something is? Neither more nor less than _sugar_!
Witness the grand manufactories at Colmar, in France, where bags of
starch are converted into casks of syrup by a process of nature alone;
so that the inhabitants of the neighborhood sweeten their coffee at
breakfast with what might have been made into rolls, had it been left
alone. And this is not all. Give back this starch-sugar into the hands
of Nature once more by putting it into certain other conditions, and a
new process begins in it. About a third of its carbon will unite itself,
of its own accord, with the two-thirds of its oxygen, so as to make
carbonic acid, (you are acquainted with that gentleman now) which shall
fly off and away, and there will remain--what do you think?--_Alcohol_,
that other combustible we talked about, and which burns even better than
sugar and starch, since in a hundred ounces it contains as follows:--
Ounces.
Carbon 53
Hydrogen 13
Oxygen 34
---
100
All this astonishes you. What would you say then if I were to tell you
that your pocket-handkerchief is composed of entirely the same materials
as starch, and in the same proportions too, and that if a chemist were
to take a fancy, by way of a joke, to make you a tumbler of sugar and
water, or a small glass of brandy out of it, he could do so if he
chose. Wonders are found, you see, in other places besides fairy tales;
and since I have begun this subject I will go on to the end. Know then
that from the log on the fire, to the back of your chair, everything
made of wood, is in pretty nearly the same predicament as your
pocket-handkerchief; and if people are not in the habit of making casks
of syrup and kegs of brandy out of the trees they cut down in the
woods, it is only, I assure you, because such sugar and brandy would
cost more to make than other sorts, and would not be so good in the
end. Should some one ever invent and bring to perfection an economical
process for doing it thoroughly well, sugar-makers and spirit-distillers
will have to be on their guard!
But we are wandering from our subject. If I have allowed myself to
make this digression, however, it is because I am not sorry to accustom
your mind early to the idea of those wonderful transformations which
nature accomplishes, and of which I could give you many other instances.
To return to our flour. As soon as all the starch is gone out of it,
there remains in your hand a whitish, elastic substance, which is also
sticky or _glutinous_, so that it makes a very good glue if you choose;
and hence its name of _gluten_, which is the Latin word for glue.
When dried, this _gluten_ becomes brittle and semi-transparent.
It keeps for an unlimited time in _alcohol_, putrefies very soon
in water exposed to the air, and is easily dissolved in a wash of soda
or potash. Finally 100 ounces of it contain as follows:--
Ounces.
Carbon 63
Hydrogen 7
Oxygen 13
Nitrogen 17
---
100
Observe the last material named. It is a new arrival, of which I shall
soon have something to say.
But where am I leading you? you will ask, with all these uninteresting
details about glue.
Wait a little and you shall hear.
You have probably never seen any one bled, which is a pity, as it
happens; for if you had, you might have noticed (provided you had had
the courage to look into the basin), that after a few seconds, the
blood which had been taken away separated itself of its own accord
into two portions; the one a yellowish transparent liquid, the other
an opaque red mass floating on the top, and which is called the
_coagulum_ of the blood or _clot_. This _coagulum_ owes its color to an
infinity of minute red bodies of which we will speak more fully by and
by, and which are retained as if in a net, in the meshes of a peculiar
substance to which I am now going to call your attention.
That substance is whitish, elastic and sticky; and when dried becomes
brittle and semi-transparent. It keeps for an unlimited time in alcohol,
putrefies very soon in water exposed to the air, and is easily dissolved
in a wash of soda or potash. Finally 100 ounces of it contain as
follows:--
Ounces.
Carbon 63
Hydrogen 7
Oxygen 13
Nitrogen 17
---
100
This substance is called _fibrine_. It goes to form the fibres of those
muscles which are contained in a half formed state in the blood.
You are laughing by this time I know, and I also know the reason why.
I have told you the same story twice over. You have not forgotten my
wearisome description of _gluten_, and here I am, saying exactly
the same thing of _fibrine_! You conclude I am dreaming, and have
made a mistake!
But no, I am wide awake, I assure you, and mean what I say. And if
these details are the same in the two cases, it is for the simple
reason that the two bodies are one and the same thing; _gluten_ and
_fibrine_ being in reality but one substance, so that were the most
skilful professor to see the two together dried, he would be puzzled to
say which came from the flour, and which from the blood. I mentioned
that our muscles existed in a half-formed state in the blood. Here is
something further. The _fibres_ of muscles exist previously in full
perfection, in the bread we eat; and when you make little round pills of
the crumbs at your side, it is composed of fibres stolen from your
muscles which enable the particles to stick together; and I say _stolen
from your muscles_, because they are the _gluten_ which you ought to
have eaten. I hope the thought of this may cure you of a foolish habit,
which is sometimes far from agreeable to those who sit by you.
This, then, is the first great _aliment of nutrition_, and you
may make yourself perfectly easy about the fate of those who eat bread.
If little girls should now and then have to lunch on dry bread, I do
not see that they are much to be pitied. There is the starch to keep
up their fire, and the gluten for their nourishment, and that is all
they require. The porter above is the only one who finds fault. And
in these days porters have become more difficult to please than the
masters themselves.
Then as to babies who drink nothing but milk, you perhaps wish to know
where they get their share of fibrine.
And I am obliged to own there is none in the milk itself; but, I
daresay, you know curdled milk or _rennet_? The same separation into two
portions has taken place there which occurs in the blood when drawn from
the arm; underneath is a yellowish transparent liquid,--that is the
_whey_; above a white curd of which cheese is made, and which contains a
great part of what would have made butter. By carefully clearing the
curd from all its buttery particles you obtain a kind of white powder
which is the essential principle of cheese, and to which the pretty name
of _casein_ is given because _caseus_ is the Latin for cheese. I shall
not trouble you now with details about _casein_; but there is one thing
you ought to know. A hundred ounces of _casein_ contain as follows:--
Ounces.
Carbon 63
Hydrogen 7
Oxygen 13
Nitrogen 17
---
100
Exactly like gluten and fibrine!
Now, then, you can understand that no particular credit is due to the
blood for manufacturing muscles out of the cheese of the milk which
a little baby sucks. He has much less trouble than the manufacturers
at Colmar have in turning their starch into sugar; because in his case
the new substance is not only composed of the same materials as the
old one, but contains them in exactly the same proportion also.
We have a second aliment of nutrition, you see, and I must warn you
that it is not found in milk only. It exists in large quantities in
peas, beans, lentils, and kidney-beans, which are actually full of
cheese, however strange this may seem to you. It would not surprise
you so much, however, if you had been in China and had tasted those
delicious little cheeses which are sold in the streets of Canton. They
cannot be distinguished from our own. Only the Chinese (from whom we
shall learn a great many things when we have beaten them so that they
will conclude to be friends with us)--the Chinese, I say, do without
milk altogether. They stew down peas into a thin pulp. They curdle
this pulp just as we do milk, and in the same way they squeeze the
curd well, salt it, and put it into moulds--just as we do--and out
comes a cheese at last--a real cheese, composed of real _casein_!
Put it into the hands of a chemist, and ask him the component parts
of a hundred grains of it, and he will tell you as follows:--
Ounces.
Carbon 63
Hydrogen 7, etc.
I stop there; for you surely know the list by this time!
Only the third aliment of nutrition remains to be considered, for there
are but three; and I will tell you in confidence, what is stranger
still, viz., that there is in reality but one! But we have had enough
food for one day, and I do not wish to spoil your appetite. We will
reserve the rest for another meal.
LETTER XXVII.
ALIMENTS OF NUTRITION (_continued_).
NITROGEN OR AZOTE.
There is a favorite conjuring trick, which always amuses people, though
it deceives no one. The conjuror shows you an egg, holds it up to the
light that you may see it is quite fresh, then breaks it;
and--crack--out comes a poor little wet bird, who flies away as well
as he can.
This trick is repeated in earnest by nature every day, under our very
eyes, without our paying any attention to it. She brings a chicken out
of the egg, which we place under the hen for twenty-two days, instead
of eating it in the shell as we might have done, and we view it as a
matter of course. Yet we do not say here that the bird may not have
come down the conjuror's sleeve, or the hen may not have brought it
from under her wing. It was really in the egg, and its own beak tapped
against the shell from within and cracked it.
How has this come about? No one can have put that beak, those feathers,
those feet, the whole little body, in short, into the egg while the
hen was sitting upon it, that is certain. It is equally certain, then,
that the liquid inside the egg must have contained materials for all
those things beforehand; and if Nature could manufacture the bones,
muscles, eyes, etc., of the chicken, out of that liquid while in the
egg, she would probably have found no more difficulty in manufacturing
your bones, muscles, eyes, etc., from it had you swallowed the egg
yourself.
Here, then, is an undeniable _aliment of nutrition_.
It is called _albumen_, which is the Latin word for _white of egg_. It
is easily recognized by a very obvious characteristic. When exposed to a
temperature varying from sixty to seventy-five degrees of heat,
according to the quantity of water with which it is mixed, _albumen_
hardens, and changes from a colorless transparent liquid, into that
opaque white substance, which everybody who has eaten "hard-boiled eggs"
is perfectly well acquainted with.
I will only add one trifling detail. 100 ounces of albumen contain as
follows:
Ounces.
Carbon 63
Hydrogen --
You can fill up this number yourself, can you not? And knowing the 7
of hydrogen, you may guess what follows! After what we have talked of
last time, here is already an explanation of the chicken's growth. But
let us go on.
You recollect that yellowish liquid I spoke about, which lies underneath
the _clot_, or _coagulum_ of the blood? I will tell you its name, that
we may get on more easily afterward. It is called the _serum_, a Latin
word, which, for once, people have not taken the trouble of translating,
and which also means _whey_. Put this _serum_ on the fire, and in
scarcely longer time than it takes to boil an egg hard, it will be full
of an opaque white substance, which is the very _albumen_ we are
speaking of. Our blood, then, contains _white of egg_; it contains in
fact--if you care to know it--sixty-five times more white of egg than
fibrine, for in 1,000 ounces of blood, you will find 195 of _albumen_,
and only three of _fibrine_; of _casein_, none.
Nevertheless we eat cheese from time to time. And we generally eat
more meat than eggs, and meat is principally composed of fibrine! I
should be a good deal puzzled to make you understand this, if we had
not our grand list to refer to.
Ounces.
Carbon 63
Hydrogen 7, etc.
_Fibrine_, casein_, _albumen_, they are all the same thing in the main.
It is one substance assuming different appearances, according to the
occasion; like actors who play several parts in a piece, and go behind
the scenes from time to time to change their dresses. The usual
appearance of the aliment of nutrition in the blood is _albumen_; and in
the stomach, which is the dressing-room of our actors, _fibrine_ and
_casein_ disguise themselves ingeniously as _albumen_; trusting to
_albumen_ to come forward afterwards as _fibrine_ or _casein_, when
there is either a muscle to be formed, or milk to be produced.
Know, moreover, that _albumen_ very often comes to us ready dressed, and
it is not only from eggs we get it. As we have already found the
_fibrine_ of the muscle and the _casein_ of milk in vegetables, so we
shall also find there, and that without looking far, the albumen of the
egg. It exists in grass, in salad, and in all the soft parts of
vegetables. The juice of root-vegetables in particular contains
remarkable quantities of it. Boil, for instance, the juice of a turnip,
after straining it quite clear, and you will see a white, opaque
substance produced, exactly like that which you would observe under
similar circumstances in the _serum_ of the blood; real _white of egg_,
that is to say--to call it by the name you are most familiar with--with
all its due proportions of carbon, hydrogen, oxygen, and nitrogen.
I wonder whether you feel as I do, dear child; for I own that I turn
giddy almost when I look too long into these depths of the mysteries
of nature. Here, for instance, is the substance which is found
everywhere, and everywhere the same--in the grass as in the egg, in
your blood as in turnip-juice! And with this one sole substance which
it has pleased the great Creator to throw broadcast into everything
you eat, He has fashioned all the thousand portions of your frame,
diverse and delicate as they are; never once undoing it, so to speak,
to re-arrange differently the elements of which it is composed. From
time to time it receives some slight impulse which alters its appearance
but not its nature, and that is all. As the chemist found it in the
bit of salad, so he will find it again in the tip of your nose, if you
will trust him with that for examination. We are proud of our personal
appearance sometimes, and smile at ourselves in the looking-glass; we
think the body a very precious thing; but yet when we look deeply into
it we find it merely so much charcoal, water and air.
This reminds me that we have not yet made acquaintance with the new
personage who was lately introduced upon the scene. _Nitrogen_ or
_azote_, I mean. He plays too important a part to be allowed to remain
in obscurity.
You have already learnt that oxygen united with hydrogen produces
water. Combined with nitrogen it produces air; but in that case there
is no union of the two. They are merely neighbors, occupying between
them the whole space extending from the earth's surface to forty or
fifty miles above our heads; together everywhere, but everywhere as
entire strangers to each other as two Englishmen who have never been
introduced! I should be a good deal puzzled to say what nitrogen does
in the air: he is there as an inert body, and leaves all the business
to the oxygen. When we breathe, for instance, the nitrogen enters our
lungs together with its inseparable companion, but it goes out as it
went in, without leaving a trace of its passage. Nevertheless, as
sometimes happens among men, the one who does nothing takes up the
most room. Nitrogen alone occupies four-fifths of the atmosphere, where
it is of no other use than to moderate the ardent activity of king
oxygen, who would consume everything were he alone. I can compare it
to nothing better than to the water you mix with wine, which would be
too fiery for your inside if you drank it by itself. This is what
nitrogen does. It puts the drag on the car of combustion; as in society,
the large proportion of quiet people put the drag on the car of progress
(let us for once indulge ourselves in talking like the newspapers!);
and such people are of definite use, however irritating their
interference may appear in some cases. The world would go on too rapidly
if there were nothing but oxygen among men. We have quite enough in
having a fifth of it!
But what in the world am I talking about? Let us get back to nitrogen
as fast as we can!
We must not imagine there is no energy in this quiet moderator of
oxygen. Like those calm people who become terrible when once roused,
our nitrogen becomes extremely violent in his actions when he is excited
by another substance, and is bent on forming alliances. Sometimes the
usually cold neighbor unites itself to oxygen in the closest bonds;
in which case the two together form that powerful liquid, _aqua-fortis_,
of which you may have heard, and which corrodes copper, burns the skin,
and devours indiscriminately almost everything it comes in contact with.
Combined with hydrogen, nitrogen forms _ammonia_, which is still often
called by its old name _volatile alkali_; one of the most powerful
bodies in existence, and one for which you would very soon learn to
entertain a proper respect, if somebody were to uncork a bottle of it
under your nose. Finally, nitrogen and carbon combined, produce a quite
foreign substance (_cyanogen_), resembling neither father nor mother in
its actions and powers, to the confusion of all preconceived ideas, when
Gay-Lussac, a Frenchman, introduced it to the world, where it fell like
a bombshell upon the theory of chemical combinations. This impertinent
fellow, combining with hydrogen in his turn, produces _prussic acid_,
the most frightful of poisons; one drop of which placed on the tongue of
a horse strikes it dead as if by lightning.
You perceive that you must not trust our worthy friend too far. You
have learnt, however, elsewhere, that it is not equally formidable in
all its combinations. Those very substances which, when paired off
into small separate groups, destroy all before them, constitute, all
four together, that precious aliment of nutrition of which we are
formed. Moreover, its real name is "_azotized aliment_" because
it is the presence of nitrogen or azote in it, which, above all,
determines its quality, so that people are in the habit of estimating
the nourishing power of our food by the amount of nitrogen it contains.
In fact, nitrogen seems to be a substance especially inclined towards
everything that has life. His three comrades wander in mighty streams,
so to speak, through every part of creation; but he, except in the
vast domain of the atmosphere, where he reigns in such majestic repose,
is rarely met with, except in animals, or in such portions of plants
as are destined for the support of animal life.
On this point I will tell you the history of his original name,
_azote_, which you will find curious enough. A short time before
the French Revolution, in 1789, the principal properties of this gas
were made known to the world by a learned Frenchman, who may be almost
considered the father of modern chemistry, and whose name I must beg
you to recollect. [Footnote: Dr. Daniel Rutherford (Edinburgh)
discovered the existence of _Nitrogen_, A. D. 1772; but he never
investigated its character.] He was called _Lavoisier_. While
endeavoring to account satisfactorily for _combustion_, which
before his time people explained any way they could, Lavoisier succeeded
in separating our two friends, the neighbors in the atmosphere, one
from the other, and was the first man in the world who managed to
secure in two bottles--on the one hand, the bubbling oxygen freed from
his tiresome mentor; on the other, the sober *azote, snatched away
from his giddy pupil. What he did with the bottle of oxygen matters
but little to us; but in the bottle of _azote_ he plunged, by way
of experiment, an unfortunate mouse, and subsequently a little bird,
both of whom, finding no oxygen to breathe, died one after the other.
Nothing could live in it, as you may suppose; and Lavoisier thought
it must be right to give so destructive a gas the name of _azote_,
which in Greek means "_opposed to life_." Meantime, science went
on progressing by the gleam of the lamp he had lit, and then followed
the discoveries of his successors, who forced their way into the obscure
laboratory where the elements of living bodies are prepared. And at
last it was ascertained that this _azote_, opposed to life as it
was thought to be, was actually an essential property of life; that
it accompanied it everywhere, and that without it the whole framework
of the animal machine would fall to pieces. It is still known by its
old name, which custom had sanctioned; but I imagine no learned man
can ever utter it now without a feeling of humility, and without the
thought that the future has possibly many contradictions in store for
him also. Besides, nitrogen has to pass through many fine-drawing
processes before it attains that post of honor which has been assigned
to it in the animal kingdom. The animal himself can do nothing with
it, unless it has been previously absorbed and digested by the
vegetable, and the vegetable in its turn could get no good from it,
were it to remain isolated and indifferent in the bosom of the
atmosphere. It is only when it has formed one of those combinations
I have been telling you about, and more particularly the second, which
produces _ammonia_, that it fairly enters upon the round of life.
And then, in the mysterious depths of vegetable existence is organized
that wonderful _quadrille_ of the _aliments of nutrition_, the history
of which has now been sufficiently explained to you.
The vegetable kingdom, therefore, is simply the great kitchen in which
the dinner of the animal kingdom is being constantly made ready; and
when we eat beef, it is, in fact, the grass which the ox has eaten,
which nourishes us. The animal is only a medium which transmits intact
to us the _albumen_ extracted in his own stomach from the juices
furnished to him in the fields. He is the waiter of the eating-house;
the dishes which he brings us have been given him already cooked in
the kitchen. But to appreciate properly the service he renders us we
must remember that the dishes to be obtained from grass are very, very
small, and that it would be a great fatigue to the stomach if it could
only get at such tiny scraps at a time; as, alas! has sometimes happened
to the famine-stricken poor, who have tried in vain to support life
from the grass in the field. But these minute dishes are brought to
us in the mass whenever we eat beef, and our stomachs benefit
accordingly. Do not forget this, my child; and when mamma asks you to
eat meat, obey her with a good grace; if, that is to say, you wish to
grow up to be a woman.
LETTER XXVIII.
COMPOSITION OF THE BLOOD.
One word more before we finish. We must not leave off without bidding
a last farewell to the good servant of whom we have spoken so much;
the model steward so exact in giving back everything he receives--the
factotum of the house in short. We have watched him at work long enough,
but I have not yet described him personally to you, nor told you exactly
what he is composed of.
And here I shall be obliged to begin again with figures and
calculations, although I am told young people are not very fond of
them. Nevertheless, none of us can manage our affairs properly without
them. Hereafter, when you are at the head of a family, you will be
obliged to practise arithmetic, if you want to know what is going on
in your house. Never allow yourself to look upon what is necessary as
wearisome; the true secret of being punctual in our duties is to throw
our heart and interest into them.
I choose, therefore, to suppose that you will be interested to know
that 1000 ounces of blood generally contain, (for there are shades of
difference between one sort of blood and another) 870 ounces of the
_serum_ I have been talking about, and 130 ounces of _clot_. At first
sight one would take the quantity of _clot_ to be much greater than it
really is; but in the state you see it, in the basin, it contains a
considerable amount of water, which belongs by right to its companion
_serum_, and which has to be drained away from it before it can be
weighed.
Now, in our 870 ounces of serum, we shall find, to begin with, 790 of
water; do not be astonished at the quantity. Most of the weight of all
animals is produced by water; they weigh comparatively nothing after
being thoroughly dried in a stove--when they are dead of course--for
neither animal nor plant can live unless saturated with water. This,
by the way, may serve to explain the ease with which we can keep
ourselves floating in water; we are not much more than water ourselves!
Were it not for those abominable bones which are a little bit heavier
than the rest, we should never sink unless a stone were hung round our
necks.
I repeat then; 790 ounces of water in 870 of _serum_, which leaves 80.
Of this, _albumen_ furnishes seventy, and the ten others, with the
exception of a small portion of fat which floats here and there
ready-made, are _salts_. It would take too long to explain what _salts_
are here, but there is one sort of salt you know perfectly well; viz.,
that which is put on the dinner-table in a salt-cellar. And it is the
most important of all. More than half the ten ounces of salts consist of
it alone, which will make you understand better than before, what I
explained with reference to the stomach; that is, why we put salt in our
food. The porter above is quite up to his business when he asks everyone
who enters to produce his little bit of salt. It is an attention which
the blood appreciates very highly, although table-salt is of no great
use to him in his building operations; but it evidently keeps him in
good humor, and he would work badly without it. It is the same with all
the animals man makes use of, and even the plants he cultivates, find
that salt gives them an appetite. And it would almost seem as if nature
had purposely dealt with us in this matter on a magnificent scale. She
has made salt-magazines of the sea and the bosom of the earth, where it
exists in prodigious masses which cost nothing but the labor of stooping
to pick up, except in countries where a gentleman called a tax-gatherer,
stands by to count the lumps and allow them to pass on by paying a
duty. For my part, if I were the government--this is a secret between
you and me, mind--I would look out for something else to stand in the
place of the salt-tax. It is not well to interpose between man and the
gratuities of Dame Nature, and to make him pay more heavily for the
blood's chosen friend than she meant him to be charged.
But to proceed, the kitchen-salt being deducted from the ten ounces
of salts-in-general, there remain altogether from four to five ounces,
which contain----. But here I stop, for it puzzles me very much how
to go on! Enough, that to enable you to follow me, you would require
at least as much knowledge of chemistry as will be expected of a young
man who has to pass an examination in medicine. Fancy the contents of
a whole druggist's shop! I will tell you a few names, that you may
have a specimen of the style in use, but I forewarn you that they are
not inviting: _hydrochlorate of ammonia; hydrochlorate of potash;
carbonate of lime; sulphate of potash; phosphate of lime; phosphate
of magnesia; lactate of soda._ I spare you the others, for many
others there are, without counting those which have not yet been
discovered I All these things are to be found, I must tell you, in
fibrine and albumen, but in such minute quantities that it is scarcely
possible to recognize them.
In the serum, for instance, the gentlemen are so very small, and so
completely entangled one with the other, that it is startling to think
of the skill and patience requisite for making them all out, to say
nothing of affixing the right name--uncouth as it may seem--to each
grain of this almost imperceptible dust! He who first called man an
epitome of creation, scarcely knew how truly he was speaking, for man
bears about in his veins, ascertained samples of at least half the
primitive substances from which all others are made, and if the whole
of them should some day be found to be there, I for one should not be
surprised.
This is well worth knowing, is it not? and I have not come to the end
of my story yet.
We have still the 130 ounces of _clot_ to speak about. But their
contents are easily reckoned. Three ounces of fibrine and 127 of
_globules_.
Here, however, we enter upon such a world of wonders, that I am quite
delighted to be able to finish with it. It will be the masterpiece of
our exhibition!
You feel quite sure blood is red, do you not? Well! it is no more red
than the water of a stream would be, if you were to fill it with little
red fishes. Suppose the fishes to be very very small, as small as a
grain of sand; and closely crowded together through the whole depth
of the stream: the water would look quite red, would it not? And this
is the way in which blood looks red: only observe one thing; a grain
of sand is a mountain in comparison with the little red fishes in the
blood. If I were to tell you they measured about the 3,200th part of
an inch in diameter, you would not be much the wiser, so I prefer
saying (by way of giving you a more striking idea of their minuteness)
that there would be about a million in such a drop of blood as would
hang on the point of a needle. I say so on the authority of a scientific
Frenchman--M. Bouillet. Not that he ever counted them, as you may
suppose, any more than I have done; but this is as near an approach
as can be made by calculation to the size of those fabulous
blood-fishes, which are the 3,200th part of an inch in diameter.
These littlest fishes are called _globules_; but they are not
exactly shaped like _little globes_, as the word would lead you
to suppose. They are more like little plates slightly hollowed out on
both sides. The central nucleus is surrounded by a flattened margin
rather bladdery in appearance, of a beautiful red color, formed of a
sort of very soft and very elastic jelly. I scarcely need tell you
that all this was discovered through the microscope, and moreover, by
examining the blood of frogs, in which the globules are much larger
than in ours. [Footnote: Authentic portraits of these globules drawn--so
to speak--by Nature herself, are to be seen on the admirable Photographs
obtained by Bertsch, with the aid of the solar microscope, invented
by himself and Arnaud. There you see them magnified 250,000 times, and
may study them at your ease, and verify my description for yourself
without any fear of being deceived. You must persuade your father to
procure one. This result of photography is among the wonders of modern
science.]
It was in 1661--rather more than two hundred years ago--that an Italian
and a Dutchman discovered, each by himself in his own country, the
microscopic population of the blood. The name of the Italian is not
very difficult--_Malpighi_. As to the Dutchman's, you must pronounce it
in the best way you can--he was called _Leeuwenhock_. You smile, but he
was nevertheless one of the first men who really comprehended what a
wonderful auxiliary human science had just got hold of in the
microscope, and he has helped to open the eyes of the world to the
marvels of miniature creation. So content yourself, young lady, with
mis-pronouncing his name, and beware of laughing at it! Names are
something like faces, one may live to be ashamed of ridiculing
the wrong one.
This discovery of the globules of the blood, was destined to throw
great light upon the way in which the _nutrition of the organs_
was carried on. Modern chemists, who are always fond of investigation,
have examined what they are made of, and can find little else in them
but _albumen_. Out of our 127 ounces of globules, 125 are albumen;
and these, with the 70 ounces which we found before in the serum, make
up the 195 ounces (of albumen) which I told you were contained in the
1,000 ounces of blood. Forgive me all these ounces and figures. Exact
accounts give exact information.
These globules, then, are composed almost entirely of albumen. Nearly
two-thirds of all the albumen in the blood is concentrated in them;
and you know now the use of albumen, viz., that it is the foundation
of all the buildings of which the blood is the architect. Everything
leads us to believe that the formation of globules in the blood is the
last touch given by nature to that magical provision begun in
thevegetable, continued in the stomach, and finished in the veins, to
which, in combination with carbon, hydrogen, oxygen, and nitrogen, we
are indebted for the subsistence of every portion of our body. Thus
the blood-globules may be considered as albumen which has finished its
education, and is ready to go into the world; while the albumen of the
serum is, like our young friends, the generations in reserve, who are
still at school awaiting their turn.
This is more than a mere supposition. Scientific men have taken to
themselves, on their own authority, all sorts of rights over animals,
and we profit basely enough by their crimes--I will not withdraw the
word--in order to increase our knowledge. Accordingly, they conceived
the idea of opening the veins of animals, and allowing the blood to
flow until the victim was prostrate and motionless as a corpse. This
done, they proceeded to fill the exhausted veins with blood, similar
to that which had been withdrawn, and with the blood, life was seen
gradually to return, till the animal rose from the ground, walked, and
resumed its disturbed existence, as if nothing had happened. The
interesting part of the experiment to us is, that if serum only, without
globules, be restored to the unfortunate animal, it is of no use
whatever, and the corpse does not revive.
It is evident, then, that all the power and virtue of the blood lies
in the globules; and according as their number is great or small it
is "rich" or "poor," as it is called; and where their number is not
up to the mark, the blood acts more feebly on the organs, life is
calmer, and people are no longer troubled with emotions--in other
words, with violent heats of the blood. Hence the impassible character
of _lymphatic_ people, who often get on in the struggle of life
better than others, because they are never in a hurry, and know how
to wait for opportunities. You will occasionally hear the word
_lymphatic_, for it has become the fashion, and it is time for
me to explain it; but unluckily the explanation is not in its favor.
You remember those little scavengers we spoke about formerly, who came
from the depths of all the organs, carrying away with them the worn-out
building materials, and covering the surface of the body with an
inextricable net work of tiny canals. These canals are called
_lymphatic vessels_, in consequence of being filled with a liquid
which is called _lymph_ (_water_, in Latin), but why I cannot
tell you, for it is, in fact, simple _serum_. There was a very
simple way of ascertaining this by making out an inventory of the
contents of the _lymph_ liquid, and when this was done, they were
found to consist of water, albumen, and the salts of serum; there was
even a little fibrine; the only thing wanting was _globules_.
How the truant serum finds its way into the lymphatic vessels is
probably as follows:--I have already mentioned the inconceivable
delicacy of the capillary vessels, those last ramifications of our
arteries and veins. It needs all the impulsive power of the heart to
enable the blood to force its way through these narrow passages; and
minute as are the globules, it would seem that they have but just room
to pass, for in examining under the microscope a corner of the tongue
of a live frog, the globules have been seen doubling themselves up to
pass through the capillaries, resuming their natural form afterwards.
It was this, indeed, which made me tell you just now that their margins
were elastic. During this momentary crush, part of the serum being
forced on too fast, oozes through the wall of the over-filled
capillaries, as water oozes through the leathern pipes of a fire-engine,
and hence probably the appearance of serum or _lymph_ in the organs,
where it is immediately sucked up (i. e., _absorbed_) by the lymphatic
vessels. Now, you will easily understand that the larger the proportion
of serum in the blood, the greater will be the quantity to be expelled
in passing through the capillaries, and the more will the lymphatic
vessels swell. In such cases the temperament or constitution is said to
be _lymphatic_. If, on the contrary, the globules are in excess, the
lymphatic vessels receive less serum, and diminish in size. The
temperament is then called _sanguine_, as if there were no serum in the
blood. You shall be judge yourself, knowing what you now do, whether it
would not be more reasonable to call such temperaments _serous_ and
_globulous_. At any rate those names would give people an idea of the
real state of things, and teach them that there were such things as
globules in the blood.
[Footnote: Here is a summary of the contents of 1000 oz. of blood:--
Ounces.
Water................... 790
Serum. Albumen...................70 870
Salts.................... 10
Fibrine................... 3
Clot. Globules Albumen.. 125 130
Coloring matter...... 2 127
----
1000
----]
To conclude, I must give you an account of the two ounces which still
remain of the 127 of globules, albumen taking up only 125, as you know.
Those two poor little ounces--the remainder of the thousand with which
we started--would you believe it?--they alone have the honor of
conferring upon the blood its beautiful red color. They constitute the
coloring matter of the globules, and you will never guess its chief
element. It is iron; ay, actually iron, young lady--the iron of swords
and bayonets. We often accuse it of tingeing the earth with blood; and
you may now know further, that it reddens blood itself by way of
compensation. Do not trouble yourself as to where it comes from. Our
fields are full of it, our very plants have stores of it. It sometimes
happens that our digestive apparatus, put out of order by other
occupations, fails to make use of the amount of iron offered to it;
in which case the blood is discolored, and the face turns pallid as
wax: this is an illness requiring great care. If it should ever befall
you, you will not be surprised, after to-day's lesson, to hear the
doctor say that you must have some iron. But be easy--you will not
have to swallow it whole! If you will take my advice, you will obey
the doctor's orders as soon as you can.
Not that looking pale signifies any thing: indeed, some young ladies
think it an advantage. But it is no advantage to any body when the
blood-globules are distressed for want of their proper supply of iron,
and do their work grudgingly, like ill-fed laborers. Nothing can go
on without them, you know, and they are people whom it is not well to
leave too long out of sorts. Else languor comes on; languor which is
the beginning of death: and pray remember that iron, which so often
causes death, is equally useful for keeping it at bay. By sending it
to the discolored globules, you give them back their energy and
brilliancy together.
I have come here to the end of all that is known with any certainty
about these wonderful globules which are to us the medium of life.
Shall I go further, is the question, and take you with me into the
fields of supposition, so full of noxious weeds? And yet why not?
Science owes its present position to the praiseworthy rule of never
adopting any theory which is not supported by well-established facts;
and I would be the last to advise a change. Were I to tell you, what
I am now going to say to you, at a meeting of the British Association
of Science, they would turn me out of the room, and with very good
reason. Nothing ought to be taught there but what can be proved. But
this is of no consequence to you and me, and we have a right to amuse
ourselves a little, after having worked so hard.
Well, there is an idea which nothing shall ever drive out of my head,
however imperfectly it may be proved as yet; namely, that each of our
globules is an animated being; and that our life is the mysterious
result of these millions of lesser lives, each of them insignificant
in itself; in the same way that the mighty existence of a nation, is
a compound of crowds of existences, each, for the most part, without
individual importance. Take our own or any other country as an instance;
where millions of brains, many of them by no means first-rate in power,
go to form a national character, the highest (as each _nation_
is apt to think of itself) in the world. According to this idea, you
must be a sort of nation yourself, my dear child, which is gratifying
to think of on the whole.
This is much more extraordinary than what I told you some time ago,
of the individual life of the organs, each of which on this new system
would be a province in itself! Do not exclaim too hastily. Whether the
globules are animated or not, it is very certain, let me tell you,
that your life depends entirely upon them; that it is weakened if they
are weakened; that it revives with them; and that whether you attribute
individual life to them or not, makes no alteration in the fact: their
action upon you remains the same. And he must be a very clever man who
can show me the exact difference between action and life. Hereafter,
when we have descended the scale of the animal world together, and are
arrived at the study of what are called microscopic animals, you will
better understand the words which appear so strange to you now. What
little our feeble instruments have revealed to us so far, of the history
of those globules, places them almost on a level with those strange
creatures, inexplicable to us, which are found in innumerable
multitudes, in a variety of liquids. We trace in them the beginning
of organization; their form and size are alike in all individuals of
the same species; and species vary enough to induce one to believe,
that there is a necessary relation between an animal's way of life and
that of its globules. If the microscope has not yet caught them in any
overt living act, who can be surprised? it is only dead blood which
has been submitted to the test. They ought to be observed in the
exercise of their functions, in the living animal itself, as has been
done to some extent in the frog; and if our foolish chat could influence
scientific observers, I would say to them what M. Leverrier said years
ago to the astonished astronomers: "Look yonder; you ought to see a
light there with which you are not yet acquainted!"
I am carrying you a long way on the wings of my fancy, my dear child;
but have no fears; I will not let you fall. This life of our globules,
which would, after all, be only one mystery the more among many, opens
before our eyes a magnificent vista of the uniformity in the scheme
of creation; which goes on repeating itself, while enlarging its circles
to infinity. We may, all of us, be only so many globules of the great
invisible fabric of humanity, in which we go up and down one after
another; and those vast globes which our telescopes follow through
celestial space, may be but globules of one, as yet unknown, to which
the Almighty alone can give a name.
Take this page to your father, my dear child, if you do not understand
it rightly; and now, shake hands, my history is ended!
PART SECOND--ANIMALS.
LETTER XXIX.
CLASSIFICATION OF ANIMALS.
'It is dangerous to show man how much he resembles the beasts, without
at the same time pointing out to him his own greatness. It is also
dangerous to show him his greatness, without pointing out his baseness.
It is more dangerous still to leave him in ignorance of both. But it
is greatly for his advantage to have both set before him.'--_Pensées
de Pascal_.
The man who wrote that, my dear child, did not trouble himself much
about children. He was one of the gravest specimens of literary
genius--a man who can scarcely be said to have ever been a child
himself; for as the story goes, he was found one day, when only twelve
years old, inventing geometry, and his father only saved him from
trouble, by putting the great book of Euclid into his hands; and, at
sixteen, he wrote a treatise on _Conic Sections_, which was the
wonder of all the learned men of the day. I have not a very clear idea
of what Conic Sections are myself; but I tell you this to show that
Pascal was a very profound and learned man, under whose authority,
therefore, I am very glad to take shelter, now that I am going to set
before you the very startling points of resemblance which exist between
you and the beasts.
As to your greatness, it delights me to explain it to you. It is not
due to the handsome clothes you wear when you are going out, nor to
the luxurious furniture of mamma's drawing-room, but to the possession
of that young soul which is beginning to dawn within you, as the sun
rises in the morning sky, and pierces through the early mists; in that
growing intelligence which has enabled you to understand so far all
the pretty stories I have told you; in that fresh unsullied conscience,
which congratulates you when you have been good, and reproves you when
you have done wrong: all of them gifts which are not bestowed on the
lower animals, or certainly not to the same extent as upon you--gifts
by which you rise more and more above them, the more they are developed
in yourself. Your baseness--but, begging Pascal's pardon, I cannot
call it baseness--your connecting link with the brute creation lies
in those other gifts of God which you and they share in common--in
those wonders of your organization, which we shall now meet with in
them again, in full perfection at first, and that in every respect;
by which fact you may learn, if you never thought of it before, that
the lower animals come from the same creating hand as yourself, and
ought to be looked upon to some extent as younger brothers, however
distasteful such a notion may seem at first. Societies have been
established of late, both in France and England, for the protection
of animals; and a noble and honorable task they have undertaken, in
spite of the jokes that have been made at their expense. It is a
mischievous cavil to tell people who are doing good in one direction,
that more might have been done somewhere else. Everything hangs together
in the progress of public morality, and you cannot strike a blow at
cruelty to animals without at the same time making a hit at cruelty
to man. And the best argument in favor of the rights of beasts to
protection, will be found in the tour you and I are now going to make
together through the different classes of the animal creation.
Let us begin with the horse--one of the beasts which oftenest needs
our protection. Give him the mouthful of bread whose history we have
just finished. He accepts it as a treat, and needs no pressing to eat
it. And if it could tell you all its adventures afterwards, you would
find that you were listening to precisely the same story as your own
over again; that nothing was different, nothing wanting. First of
all--teeth to grind it, and a tongue to swallow it with, as a matter
of course. Next a _larynx_, which hides itself to avoid it, and an
oesophagus,* which receives it, just as in your case; a stomach with its
_gastric juices_, the same as yours, in bagpipe form, and its _pylorus_,
like your own; a _lesser intestine_, into which bile pours from a liver
like yours; _chyliferous vessels_ which suck up a milky chyle, as with
you; farther on a _large intestine_; and so on to the end. Nor is this
all:--the horse has also a heart, with its two _ventricles_, and its
double play of valves; a heart which the little girl in our tale might
confidently have exhibited to the engineers as her own, but that it
would have been somewhat too big, of course; into which heart, as into
ours, comes _venous_ blood, to be changed afterwards to _arterial_; in
lungs to which the air keeps rushing, forced thither by the see-saw
action of a _diaphragm_, as faithful a servant to him as to you.
And those lungs like our own, are a charcoal market: the same exchange
takes place there, of carbonic acid for oxygen, as in ours, an
unanswerable proof that the stove inside the horse burns fuel in the
same way as our own: and if you were to place the thermometer inside
his mouth (for we are polite enough to call it his mouth), it would
mark 37 1-2 degrees of heat (centigrade)--a difference from ourselves
not worth mentioning. Finally, if you examine his blood, you will meet
with the same _serum_ and _clot_, the whole company of _hydroclorates,
phosphates, carbonates, &c._, from which we shrank before, and globules
made like your own; having the same construction, and the same life, or
action, if you like it better. I need scarcely add that 100 oz. of its
_fibrine_ and _albumen_ contain:
Of carbon......... 63 oz.
Of hydrogen........ 7
This is understood all along as being the case everywhere, from man
down to the turnip; so that, like you, this noble animal, as the horse
is called, is in point of fact only so much carbon, so much water, and
so much air, joined to a handful of salt, which represents the earth's
share in the bodies of animals.
You must confess that, if we cannot quite call the horse a
fellow-creature, he is nevertheless very like us. And it is the same
with all those animals which man makes use of as his servants, and
which have really a sort of right to the protection of society, since
they form, to a certain extent, a portion of the human family. I do
not speak here of the dog, who pays his taxes, poor fellow, in his
quality of friend to man.
When I think of the almost identical organization of man and his
next-door neighbors, I am astonished how it could possibly have come
into the head of a certain learned individual (I will not mention his
name), when drawing up a plan of natural history, to give to man a
separate kingdom, as a sequel to the three kingdoms already
established--the mineral, vegetable, and animal. One might have forgiven
Pascal if such an idea had got into his head after writing his treatise
on Conic Sections; there being nothing in them to throw light on such
a subject. But in a naturalist, an observer who had spent his life in
the study of living creatures, the thing seems almost incredible.
Possibly he had reasons for what he did, but he certainly did not find
them in the subjects of his studies.
Forgive me, my dear child, for forgetting you in this fit of indignation
upon a point you cannot care much about. It leads me naturally enough
to my present business, which is none of the easiest, but you must
help me by paying attention. I am going to describe the _classification
of the animal kingdom_.
There are a terrible number of animals, as you know; and if we wish
to study them to any real purpose, we must begin by introducing some
sort of order into the innumerable crowds which throng, pell-mell,
around us for observation. We should otherwise never know where to
begin, or when we had come to an end.
There are many ways of setting a crowd in order, but they all go upon
the same plan. The individuals composing the crowd are parcelled off
into companies, each company having a distinguishing mark peculiar to
those who compose it. Thus the first division is into a few large
companies, which are afterwards subdivided into smaller ones, and those
into others still less, until the divisions have gone far enough. And
this is what is called a _classification_.
Let us imagine, as an example, a large crowd in a public garden; I
will soon classify it for you. I shall put the men on one side and the
women on the other. Then--to begin with the women--I shall subdivide
them into married and single. Then among married women I shall make
a company of mammas, and another of those who have no children. Among
the unmarried I shall have a group of those who have never been
married--girls, that is--and another of widows--those who were once
married, but are so no longer. Then, following the girls, I shall
separate them into tall and short. And among the short ones I shall
divide the brunettes from the blondes, and so I shall get at last to
a little blonde girl, whose classification (were she a soldier) in
military rank would be as follows:--_squadron_ of blondes; _company_ of
shorts; _battalion_ of girls; _regiment_ of unmarried women; _division_
of women. The division of men could be carried out in the same manner;
and thus we should classify our mob into complete military order. This
is easy enough, however; but the classifying of animals is a very
different affair, and I will tell you why. We ourselves require a
classification to study them by, though none was needed for their
creation. The Almighty has formed them all on one uniform plan, around
which He has, if I may so express it, lavished an infinity of
modifications separating species from species, yet without placing
between the different species those fixed barriers which we should
require now to enable us to classify them strictly. You who are learning
the pianoforte have perhaps been told the meaning of a _theme_ of
music--the first idea of the composer who follows it throughout the
piece from one end to the other, embroidering on it, as on a bit of
canvas, a thousand variations melting one into another. Such is pretty
nearly, if we may venture the comparison, the way in which we can
picture to ourselves the Almighty moving through the work of animal
creation. Step in afterwards and divide away into regiments and
battalions, if you please. Nature permits it, but she will never,
to accommodate your classifications, separate what in her is really
united.
There is still a way, however, and that is to do as I did just now in
the case of the crowd. To take, viz., only one _character_ (as we call a
distinguishing mark in natural history), and to throw together all the
individuals which possess it, the blondes, the shorts, the girls, &c. In
this way it may soon be done; but what is the result? You are in one
class, your eldest sister is in another, your mamma in a third, and your
brother in a different division altogether, a long way from you all.
Such a classification is called _artificial_, and you can see at once
that it is worthless.
The most natural plan is to put together those that are of the same
family; and the classifications made on this principle are called
_natural_ classifications.
It is a classification of this sort which has been adopted for the
animal kingdom. People have taken all the animals which possess in
common not one character only, but a collection of characters of the
most important kind, _dominant characters_, as they are called;
and of these animals they have formed, to begin with, large primary
groups; subdividing these afterwards according to the secondary
differences, which distinguish different species in the same group
from each other.
In this manner all the different sorts of animals are included in
different systematic divisions of one vast whole, through which it is
easy to find one's way, because there is a beginning and an end; and
in which animals of the same family are always grouped side by side.
Were I to mention all the divisions of this immense classification at
once, you would find the account a little long, and not very amusing.
We will go through them by degrees therefore, and, to simplify matters,
will, throughout the whole, only consider those particular characters
which are connected with our special study, the nourishment of life,
that is to say: so that you will always find yourself on well-known
ground.
I must tell you once for all, however, that it is with this as it is
with grammar. Here and there are--and it cannot be avoided--certain
exceptional cases which keep protesting timidly against the
arbitrariness of rules; but no matter; we must be contented with what
we can get, and be grateful into the bargain to those who have given
us this skillful classification, at once so ingenious and useful, in
spite of its inevitable imperfections. What is impossible is expected
of nobody. You could not understand, even if I wished to explain it
to you, the amount of science, labor and genius requisite for making
out that long list, which, tiresome as it may seem to children, is
absolutely beautiful in the eyes of learned men; too beautiful, perhaps,
and I will tell you why when we have finished. Meantime, as the best
reward we can give to those who have done us some great service is to
teach their names to children, I will tell you, before bidding you
good-bye, to whom we owe this classification, the details of which I
do not enter upon to-day.
In the first place, we owe the method employed in its establishment,
the method of _natural classification, i.e._, to a learned man
of the last century--a learned Frenchman, Bernard de Jussieu--who tried
it upon plants; another large flock by no means very easy to put in
order, as you may convince yourself any day by studying botany. The
man who applied this system to animals was also a learned Frenchman,
the clearness of the French mind adapting them peculiarly for that
sort of work. And he, too, is one of the glories of that nation. His
labors and discoveries gave a perfectly new impulse to the study of
nature. It was George Cuvier, whose statue you may see at Montbéliard,
if you should ever go there. Not that Cuvier carried through this
gigantic work alone, though the credit of it is justly his due, he
having directed and inspired it. He was assisted by many. But among
his assistants there was one, Laurillard, the most modest, yet the
most active of all, whose name I will mention also, because, like the
others, more or less celebrated, he has never had his reward. [Footnote:
In the earlier editions of this work, there was, in this place, a
severe reproach upon Cuvier for not having given proper credit to
Laurillard. This reproach I have since learned was unjust. M.
Valenciennes himself, one of the most illustrious of the collaborators
of the great Cuvier, has written me a letter in which he defends the
reputation of his friend with a warm indignation which does honor to
both of them; and cites passages in which Cuvier has spoken of
Laurillard, and among others, in the third volume of the _Ossements
Fossiles_, p. 32, ed. of 1822.]
It only remains for me, therefore, to let the lash, which I was laying
upon the shoulders of another, fall now upon my own, and to deplore
the too great facility with which I had credited, without sufficient
proofs, an assertion which I had otherwise good reason to believe to
be exact--coming to me, as it did, from Montbéliard himself, on the
testimony, it is said, of the family of Laurillard. From this avowal,
a little painful, I confess, my young readers may learn the
inconvenience of rashly condemning others! As I said in the concluding
passage, which truth, only too late, now compels me to suppress--"The
truth is sure to come out at last."
LETTER XXX.
MAMMALIA. (_Mammals_.)
Do you remember of my talking of the _vertebral column_ when I was
describing that great artery, the _aorta_, to which it forms a rampart
of defence? I should not have named it without explanation, but that you
had only to pass your hand down your back to find out what it was. Now
the _vertebral column_, or backbone, is one of those _dominant
characters_ which always carries along with it a train of other points
of resemblance in the animals where it is found. It has been chosen,
therefore, as the rallying-point of the first great group. I must tell
you beforehand that there are four of these groups, four large
companies, _i.e._, which naturalists have called by various names; as
Groups, Sections, Primary Divisions and even Branches; in this case
comparing them to four great branches of a tree, going off in different
directions from the same trunk.
And, first of all, we have to begin with the group of the
_Vertebrata_--vertebrata animals--vertebrata being a word which
explains itself.
Of course we ourselves belong to this group. In fact, we are at the
head of it; but it descends far below us. It goes on to the frog and
the fish, and includes the monkey, the ox, the fowl and the lizard;
for all these creatures possess the vertebral column. The frog does
not appear to be very much like us at first sight; and yet, by virtue
of its vertebra, it has its points of resemblance to us, which are
worth the trouble of considering. Vertebrated animals are all furnished
with a head, containing a brain, which gives its orders to the whole
body; they have all an internal skeleton, that is to say, a system of
bones linked together, forming a solid base by which all the organs
are supported. I was going to add that they have all four limbs; but
here the serpent glides in to call me to order, and to hiss at our
childish craving for fine-drawn divisions, in perfect order, where
there is an exactly proper place for everything. However, each has,
without exception, a heart, with its network of blood-vessels; red
blood, under its two conditions of arterial and venous; and also a
digestive tube, acting, on the whole, pretty much like our own. I do
not insist, mind, upon this last point, viz., that of the digestive
tube; for we shall see, by-and-by, that it is a character beyond the
pale of the primary groups. It is the fundamental character of the
trunk itself, which necessarily exists, therefore, in all the groups;
and, as I told you in my first letter, you will find it everywhere.
This is--to let you into the secret at once--the theme on which the
Great Composer has based all His infinite varieties of animal life;
and herein lies the uniformity of the animal creation, that startling
uniformity which has given so much offence to many learned men, and
which is so obvious that it will strike you of itself, I feel sure.
But I reserve this subject to the end of my letters, when you will
have heard all, and be able to judge for yourself.
It would be plunging back into confusion to attempt to examine all the
vertebrated classes at once. After making a division you must go on.
The groups have, therefore, been subdivided into _five classes_, which
we will study in succession, only naming each now: viz. _mammals_,
_birds_, _reptiles_, _fish_, and _batrachians_. Do not alarm yourself at
this last name: it is a Greek word, meaning simply frogs.
The mammals are our immediate neighbors. Mammalia are the animals which
produce milk. They bring forth their young alive, and give suck to
them as soon as they are born. This was your first nourishment, my
dear child, so you yourself are a little mammal.
What I said to you in the last letter about the horse, applies pretty
nearly as well to all mammals. We shall not, therefore, have any great
variations to notice here. Nevertheless, as these are the animals which
interest us most nearly, as they are in fact our nearest of kin, so
to speak, and those with whom we have the most to do, we will now pass
in review the different orders of which their class is composed. I
must explain to you that the _classes_ are subdivided into
_orders_, the orders into _families_, the families into
_genera_, the genera into _species_; as in armies divisions
subdivide into regiments, regiments into battalions, &c. It became
necessary, moreover, to make use of special names, in order to make
these subdivisions comprehensible, and the following are those which
have been adopted.
ORDER 1. _Bimana (two-handed)_.
Here we may pass on at once, for we have discussed this order enough
already. We are _bimane_ ourselves, since we have the distinction
of possessing two hands. Yes; that is the pretty title which the
professors have been so polite as to give us, instead of leaving us
simply our proper name of man. Yet it would have been very easy to do
this, seeing that we are the only family, the only genus, and the only
species of the order. In railway travelling, people of distinction
have a reserved carriage to themselves: so we decidedly deserve an
order to ourselves; but that is not quite the same as a separate
kingdom. In short, you are a _bimane_; so make the best you can of it.
ORDER 2. _Quadrumana (four-handed)_.
These, as their name indicates, have four hands: two at the end of the
arms, and two at the end of the legs; such are the monkeys. There is
nothing to remark; they are all alike. Stay; I am wrong, though: there
is something, insignificant it is true, but still pointing to deviation.
In some the canine teeth are set forward, _i.e._ project, and are
longer than the rest, and some species, as the ape, for instance, have
just under their cheeks convenient little pockets, which open into the
mouth, and in which they can deposit a reserve of nuts to be devoured
at leisure; these are called _pouches_.
It is a trifle in itself, but we have here a first example of the
eccentricities of nature in the construction of animals. At one time
she adds a detail; at another she suppresses one. Sometimes she is
pleased to enlarge an organ, as in the canine teeth of the monkey;
sometimes she reduces it; or perhaps here she makes its construction
more simple; there again more complicated: but still it is always the
same organ. So the dressmaker shapes the sleeves of a dress, sometimes
open, sometimes closed, flat or puffed, plain or ornamented,
pagoda-shaped or gigot-formed: but still they are all of them sleeves.
ORDER 3. _Cheiroptera (wing-handed)_.
I am quite ashamed of offering you such a word as this, my dear child.
It was a Greek fancy of the learned men, who would not condescend to
use the vulgar name Bats. In the Greek, _cheir_ means hand, and
_pteron_ wing. The Cheiroptera are animals with winged hands; in
fact, the fingers which terminate the fore-limbs of the bat lengthen
as they spread out to an extravagant extent; and are connected together
by a membrane springing from the body, with which they beat the air
as with a wing, and which enables them to fly with such ease that
theyare often taken for birds.
But, so far from really being a bird, this curious little creature has
the same internal organization as ours, and indeed comes so near us,
though without looking as if it did, that a scientific man, and a very
distinguished one too, placed the bat in the first family of the animal
kingdom, with the monkey, and, you will hardly believe it, with man.
It is found that the bat, like man and the monkey, suckles its young
at the breast; and it was this very character which Linnĉus, the leader
of artificial classification, thought of selecting as the distinguishing
mark of his first family in the animal kingdom. It is true that in
honor of the human race he had given that first family a much more
sonorous name than our usual one of _man_--viz. _primates_, the first in
rank--that is, the princes. But, alas! we were to be princes on an
equality with bats; and, for my own part, I prefer being a _bimane_, and
alone. I really believe that it was to put this saucy little creature
back into its proper place that, at the time of the great revolution in
favor of natural classification, the conclave of professors assembled at
the Botanical Gardens in Paris inflicted this horrid name of Cheiroptera
on the bat, ejecting it contemptuously from the overthrown dynasty of
the _primates_.
I have not been sorry to make you acquainted as we went along, with
this little trait in the history of classification; but beyond it there
is really nothing particular to say about the apparatus for the
nourishment of the deposed bat-princes, which is a plain proof how
nearly it must be like our own. By-the-by, there is one trifling remark
to be made with regard to her teeth. The bats we have in our country
(France), for there are many varieties of species in the world, live
on insects, which they catch in their flight by night. These insects
are often enveloped in a very hard outer case, which molars like ours
would have some difficulty in chewing properly; consequently the molars
of our little friend are fringed with conical points, and with these
she grinds down her prey without difficulty.
In America there is a large bat, the vampire, which lives on the blood
of animals, and nature has armed it accordingly. It has at the
extremityof its muzzle two sharp beak-like incisors, like the lancets of
a surgeon. The vampire bat, which roams by night like other bats, goes
straight at the large animals it sees asleep, delicately opens a vein
in the throat without waking them, and sucks their blood in long
draughts, taking care, by fanning them with its wings, to lull them
into a cool and balmy slumber. It does not, as you see, make a savage
attack on its victim: it merely inflicts a bite like that of the leech,
but the result may be death. This is the best emblem I know of the
sycophant, who undermines your soul while he fans your vanity; and
observe, while we are on the subject, that this species has always had
the art of insinuating itself among princes.
ORDER 4. _Carnivora (flesh-eaters)_.
When translated into English, this word needs no explanation. And here
we have the tribe of bears, wolves, foxes, weasels, dogs, cats, tigers,
lions, of all the fighting animals, _i.e._, those which steep
their muzzles in blood, and live by devouring others. These have a
similar apparatus for nutrition to our own; especially the bear, who,
with the monkey, is the animal most nearly resembling man, seeing that
he has feet like ours, with scarcely any tail, while the monkey has
our hands, without specifying any other points of resemblance. Like
ourselves, too, the bear is omnivorous; that is to say, it eats
everything, vegetables and fruit as well as meat; and nature, which
has given it our diet, has furnished it with molars almost exactly
like our own. Its canine teeth alone differ from ours: they are more
prominent even than those of the _quadrumana_; and this is the
case with all the members of the order, in whom we find them sometimes
developed into actual daggers. But those of them which are purely
carnivorous have molars peculiar to themselves. The lion, for example,
who does not share the bear's taste for carrots, and who would die of
hunger surrounded by the honey and grapes of which the bear is so
fond--the lion, who never takes anything but raw meat between his
teeth, has molars furnished with sharp cutting edges, intended to slice
the meat like the chopping knives used by cooks for making a hash.
The lion offers another peculiarity, which is common to him with all
the _Carnivora_. Place your finger close to the lower end of your
ear, and work your jaw; you will feel something hard moving backward
and forward against your finger. This is where the lower jaw is set
into a bone of the skull, called the _temporal_, if you care to know its
name; in other words, the bone of the temple. The extremity of the jaw
bends, and forms a kind of little knob, called _condyle_, which fits
into a cavity of the temporal bone. With us the cavity is not very deep,
nor the knob very large, so that it can play very freely; and it is this
which allows us that second movement from side to side, of which I spoke
to you formerly, and thanks to which, our little mills reduce a mouthful
of bread into paste. But this freedom of action has also its
inconveniences. You must never attempt to force too large an article
into your mouth at once--an apple, for instance--the efforts you would
then be obliged to make might easily cause the _condyle_ to slip out of
its little cavity, where its hold is but slight, and to get under the
_temporal bone_; and there you would be with your mouth wide open until
the doctor arrived. The lion, whose voracious jaw opens like the door of
an oven, so that the tamers of wild beasts have no scruple in thrusting
in their whole heads, a mouthful a good deal larger than an apple; the
lion, who has no doctors, would often be liable to this accident--an
irremediable one in his case--if nature had not made a special provision
for him. In order to secure greater firmness and strength, the second
movement is in his case sacrificed by embedding the _condyles_
deeply in their cavities, where they are fastened in such a fashion
that they can only move up and down, like the handles of a pair of
pincers. This is a restraint which enables the jaw to be safely thrown
open as wide as the fiery impulse of its terrible proprietor impels
it. Less freedom, in exchange for more power, is a bargain which any
one would gladly accept who plays the part of a lion!
I have here a remark to make. We have now passed in review three orders
besides our own, and have only had to point out a change in the
fastenings of the jaws and in the teeth; and you will find that the
same sort of modifications take place in the whole class of mammals.
This is in fact the essentially movable and variable point in their
apparatus for nutrition. The jaw and its weapons vary their character
from one species to another, according to the nature of their food;
but the modifications generally terminate there, _i.e._ on the
threshold, as it were. The interior arrangements of the house remain
otherwise much the same in all.
Here, however, in the lion, there is an interior change to be described;
but not in the arrangement of the parts, only in their size; the stomach
in this species being even smaller and weaker in proportion than ours,
and the digestive tube more than twice as short. The digestive tube
of an ordinary sized man is about seven times the length of his body,
whilst that of the lion only measures three times the length of the
animal. This is a natural consequence of the kind of nourishment he
takes. Flesh and blood, on which he lives entirely, is concentrated
_albumen_, prepared beforehand in the bodies of his victims; so
that no great preparation is needed here to convert it into lion's
blood. A professor of chemistry, who has a good assistant, does not
need a very large laboratory. This is the case with the lion; and
nature, which makes nothing in vain, has here economised space. Tame
the monarch of the forest into a domestic animal, and change his food,
and I will wager anything you please that, in the course of a few
generations, his digestive tube will lengthen itself. Examine the
inside of the cat, his little cousin, formed originally on the same
pattern as himself, and, without having ascertained the fact myself,
I am sure that, by dint of feeding it daily on sops and milk from
generation to generation, its digestive tube has become more than three
times the length of its body.
Here you ought to be told at once a very important fact relative to
the organization of the lower animals, one which places them all very
far below the order of _Bimana_, since there is such an order.
In bestowing intelligence and freedom of action on man, the Almighty
has given him the unspeakable privilege of working in His footsteps--if
I may presume to use the expression--of following up His work of
creation as it came from His hand. Now especially that man begins to
see a little more clearly into the laws of life, he has entered more
directly into the possession of this almost divine privilege, which
the Almighty has graciously vouchsafed him. You can even now have an
ox or a sheep made to order in England, giving your dimensions, as if
you were ordering a cabinet; and in a few years, if you have not asked
actual impossibilities, your commission will be executed to within an
inch. This is not said in reference to the _Carnivora_. But in
bidding you good-bye, my dear little mammal, I could not bear to leave
you under the weight of that debasing title: I wanted also to show you
your greatness.
LETTER XXXI.
MAMMALIA. _(Mammals)--continued_.
Let us continue to pass in review the different orders of the class
Mammalia. We may meet elsewhere with facts more important to science,
but nowhere with any so personally interesting to ourselves.
ORDER 5. _Insectivora (insect-eaters)_.
This order devours insects, as their name tells you plainly enough.
They feed in the same manner as the bats; consequently they have molars
like theirs, as was necessary. It is an unimportant little family, and
we will not waste much time upon it. The chief of the order is the
hedgehog, a native of our country--not very large, about nine inches
long--which lives in the woods, and which when rolled up into a ball,
with all its quills standing out, looks very much like an enormous
horse-chestnut in its shell. Its canines have not much work to do,
consequently they are very small; but, on the other hand, its two front
incisors are prolonged beyond the others, the better to seize its prey,
which creeps upon the ground. Internally there is nothing to remark
upon.
Next to the hedgehog I will mention as a curiosity the shrew or
sand-mouse, which, in spite of its name, is no mouse at all, but has
the honor, if honor it be, of being the smallest animal known of the
class Mammalia.
It is about two inches in length altogether; and if you carefully
examine its little body, you will find that it contains all the organs
you possess yourself--oesophagus, stomach, liver, intestines, veins,
arteries, heart, lungs--nothing is wanting: the machinery is absolutely
the same.
ORDER 6. _Rodentia (rodents)_.
Were we to translate this word into its meaning, namely, the _Gnawers_,
there would be some comfort in it, for we would at once know what it
means: but no matter. Rodents, or Gnawers, are rats, hares, rabbits,
beavers, marmosets, squirrels, in fact all the creatures which _nibble_.
To _nibble_, if you do not exactly understand the word, means to chew
with the points of the teeth. The rodents have no other way of eating
but by filing, if one may so say, their food with the points of two
incisors with which both the jaws are provided; these incisors are very
long, much longer even than those of the hedgehog. The next time you see
a rabbit at table, ask to see the head; and you will find that it has
four pretty little teeth, very sharp, shaped like a joiner's chisel;
that is to say, with a "bevelled edge," to use the received expression;
in other words, with one edge thinner than the other.
Here, then, we begin to diverge from the old model. First, there is a
different fastening, or _articulation_, as it is called, of the jaw. Its
_condyles_, which we saw just now in the _Carnivora_ enlarged
transversely and deeply embedded in the _fossae_ or cavity of the
temporal bone, extend here longitudinally; an arrangement which enables
the jaw to move backward and forward at pleasure, like the arm of the
locksmith when using the file. Furthermore, those little teeth, which
are constantly rubbing against each other, would be very soon worn out,
if, like our own, they were made once for all; accordingly their germ,
or _pulp_, to use the proper term, instead of perishing, as with us,
when the tooth has once come, retains its life, and works on throughout
the life of the animal. They sometimes say of a man who has not eaten
for a long while, that his teeth have grown long. This is a joke with
us; but in the case of a _rodent_ would be too serious a matter to be a
joke; for, as their incisors are always growing, like our nails, they
would soon become too long if the animal ceased for any length of time
to wear them down by eating. It is for this reason that rats and mice
have such incessant appetites, and that with them "all is fish that
comes to the net;" old books, rags, and even planks of wood, which they
will gnaw for want of something better. Come what may, they must keep up
at an equal rate the wear and tear of the incisors, and the internal
growth of the pulp beneath, which is always pushing the tooth forward.
This dull continuous work might otherwise have a terrible result, which
you would never suspect. It is very disastrous for a young lady to lose
a front tooth, as it is called, for it sadly spoils a pretty face; but
for a _rodent_ such a loss is much worse; in fact, it is a death-
warrant. The corresponding tooth, having no longer anything to rub
against, ceases to wear out; and as it does not stop growing on this
account, it lengthens indefinitely, until at last it pushes out beyond
the mouth, and places itself like a bar between the two Remaining teeth
and the food of the animal, who, poor beast, being unable to eat,
ceases to live.
The canines, whose duty it is to pierce the food, have, of course, no
use in a jaw that grinds, nor are they to be found there. Between the
incisors and the molars there is a large vacant space, which you will
easily detect if you examine a rabbit's head.
Finally, animals which can fall back in time of need on a plank for
their dinner, require a very different-sized cooking apparatus to that
of the _Carnivora_. Thus the rat, the most perfect sample of the
rodent order, possesses a digestive tube of a prodigious length, through
which the scrapings of wood have plenty of time for travelling, while
the minute nutritive particles they contain are being thoroughly
disengaged; and as every part of the animal organization tends towards
keeping our insatiable rodents in the constant state of voracity
required by its inexorable pulps, nature has given it an enormous heart
whose size exceeds even that of its stomach.
Perhaps you do not catch at once the connection which exists between
the size of the heart and of the appetite; yet it is very simple. Large
barrels are requisite for those who brew a great deal of beer, and
large hearts for those who make a great deal of blood. Now, it is the
blood, as you know, which carries heat; in other words, life, throughout
the body; when it pours in in torrents, the fire goes twice as fast,
and, consequently, the feeding must be kept up. A medical friend of
mine told me that he once had some rats sent to him--a boxful in
fact--for one of those scientific experiments which one would venture
to condemn more earnestly if their results were not sometimes
beneficial. Next morning there were only two or three animals to be
found, and these had eaten up the others. See the consequence of having
too much heart!
ORDER 7. _Pachydermata (thick-skinned)_.
In Greek _pachus_ means thick, and _derma_ skin. _Pachyderms_,
therefore, are thick-skinned animals. It is rather a vague denomination,
as you perceive, and does not tell us much about them; but it appears
that it was not very easy to find a better term. For my own part I
should be very much puzzled to find a name really suitable for such an
irregular company as this, in which all the huge beasts of the
earth--the elephant, the rhinoceros, the hippopotamus--are heaped one
upon the other, side by side with the horse, the ass, and the hog;
begging your pardon for an ugly word.
All these creatures live on vegetables, with the exception of the hog,
to whom nothing comes amiss; or who, in other words, is _omnivorous_,
like the bear, and also another member of the class _Mammalia_, which I
do not name for fear of making you blush at your companionship. This
assures you that, in the order of the _Pachydermata_, the digestive
apparatus is very fully developed. The horse, for instance, has a very
voluminous stomach, which extends much farther back than the point at
which the oesophagus empties itself; and in which, on close examination,
a sort of contraction is observed which appears to divide it in half,
producing the false effect of there being two stomachs. But, after all,
we do not find, even in this case, any essential difference to remark
upon in the internal arrangements; it is always the teeth we must look
at if we want to have something to say. There, indeed, we have only to
choose; nature has indulged herself in all manner of fantastic freaks.
To begin with the elephant, the grand master of the order, he presents
us with one of the most oddly-furnished jaws in existence. Every one
knows those two enormous tusks which protrude from his mouth, and which
furnish human industry with nearly the whole store of ivory it has
need of. Those two teeth are the largest, beyond comparison, of any
in the animal kingdom; yet they are two merely ornamental teeth,
perfectly useless in the operation of eating, and very ruinous into
the bargain to the proprietor. All those stores of the blood which
furnish the materials for ivory pass into these tusks, and, as often
happens to people who give way to a taste for luxuries, there is nothing
left wherewith to provide the animal with serviceable teeth. Those
tusks of the elephant are nothing but his upper incisors, the only
ones, observe, which curve in coming out of his jaw. In the lower jaw
he has no incisors at all; canine teeth are entirely wanting; and by
way of dental apparatus, this meagerly-furnished mouth possesses on
each side of either jaw one or two molars, enormous in size, but not
of ivory. They are composed of a number of enamelled upright layers
of tooth-substance (_dentine_), soldered together with a bony
cement; and these are our giant's only resource for chewing the grass,
young shoots, and leaves of trees, which are his natural food.
[Footnote: These teeth are nevertheless very efficient grindstones.]
As a consolation, he has the glory of knowing that he possesses the
very finest teeth in the world, the terror of all who approach him;
and I can compare him to nothing so well as to a vain woman, who is
contented to live on potatoes that she may wear fine clothes and excite
the envy of her neighbors.
The hippopotamus also has incisors in the upper jaw, which curve as
they come out of the mouth; but these never attain anything like the
size of the elephant's tusks, neither do they hinder the development
of the other teeth, of which this animal has a very respectable
collection. The upper incisors bend downward; those in the lower jaw
stand out horizontally, and terminate in sharp points like
plough-shares; and indeed the hippopotamus uses them for tearing up
the ground in order to get at the roots which form its nutriment. These
are, besides, formidable weapons, with which when enraged the animal
can tear even boats in pieces; for, as you are aware, the hippopotamus
is almost amphibious, and browses on water-plants, and lives in the
great rivers of Africa, its native country. Its name alone would have
told you this had you understood Greek; [Footnote: _Ippos_, a horse, and
_potamos_, a river. The Greeks, who had seen the hippopotamus in the
Nile, in Egypt, named it the river-horse; as afterwards the Romans
called the elephant the ox of Lucania, because they first saw it in
Lucania during the war with Pyrrhus.] but I have no complaint to make
this time, for it was the Greeks themselves who gave it. You would find
it very awkward, would you not? if you had to breakfast at the bottom of
the Thames, and could not swallow a morsel without having your nose
filled with water? But the hippopotamus labors under no such
inconvenience. Its nostrils are provided with two little doors, which it
closes at will, and behind this screen the lungs keep quite quiet while
the animal goes backwards and forwards in the water. There is generally
a hippopotamus in every large menagerie. The next time you visit one
look at him. You will see him with a large stomach almost trailing on
the ground: and no wonder; he needs plenty of room in which to stow away
all the canes, reeds, and water-plants from the bottoms of rivers, which
are not very nutritious food. Accordingly the stomach of the river-horse
presents the appearance not only of two compartments, like that of the
true horse, but looks as if it were divided into three or four.
To conclude my account of this animal, I must add that the ivory of
its teeth is even more beautiful than that of the elephant's tusks,
and that dentists carve it into very magnificent teeth for their
patients. This is not a matter to interest you much at present, but
we never know what may happen. I advise you, however, never to make
use of hippopotamus's teeth; they turn yellow very quickly, and, when
people are driven to buy teeth, the least they can try for, is to get
good-looking ones for their money.
I should like to say something about the rhinoceros while we are on
the colossal tribes, but it is a very unsatisfactory subject. The
animal has no canines, sometimes no incisors even; sometimes it has
as many as thirty-six teeth, according to the species, as naturalists
aver; and this is all I have to say about this great lump of flesh,
so misshapen outside, yet so regularly formed within. He it is who
especially deserves the title _pachydermata_, his skin being so
hard and thick that bullets glance off its surface. But this has nothing
to do with our present subject, any more than the horn upon his nose,
whose turn for description may come if I ever give you the history of
the skin and all connected with it.
The hog also has canines, and very strong ones; but it is in the wild
state, when it is called a boar, that these appear in their real form.
There we find them projecting out of the mouth with a curve, as is so
commonly seen among the _pachydermata_, forming those terrible,
sharp, and pointed tusks which have been so often fatal to the hunter.
The wild boar of the forest is supposed to be the original ancestor
of the domestic pig; and if, as is probable, this is really the case,
we have here a remarkable instance of the effect of man's treatment
upon the organisation of the animals he collects around him. The wild
boar lives only on fruits and roots, which, like the hippopotamus, he
tears up with his tusks, those safeguards of his, amid the many perils
of his life in the woods. In the service of man, on the contrary, he
becomes lazy, cowardly, and greedy; unlearns his energy and
combativeness, eats all that is offered to him in the trough, even
meat, when it happens to be thrown in; and, in order to do this
moreeasily, has recalled toward his mouth those formidable war-tusks of
his, so tremendous as weapons, so useless as teeth; has, in fact,
turned his sword into a fork. It is the case of a Tartar degenerated
into a Chinaman. [Footnote: China, about which we have heard a great
deal of late years, has been several times invaded by the warrior
hordes of Tartary. But at each time, unto the second and third
generations, the vanquishers have taken the effeminate manners, the
costume and the usages of the vanquished, and so many conquests have
only resulted in converting millions of Tartars into Chinese.]
This suggests to me an idea relative to the horse, the last important
member of the _pachydermata_ which remains to be spoken of. It
also has its canines, but very small ones; they disappear, so to speak,
in a large vacancy between the incisors and the molars, where man
inserts the bit, by means of which the animal has been subdued. Small
as these are, however, these canines indicate that the horse might eat
flesh, canine teeth being the distinctive attribute of the carnivorous
mammals. I have read somewhere, but I do not remember where, that an
unusual development of strength could be produced in the horse by
feeding it on flesh; and the old Greek poets write of a king [Footnote:
Diomed, King of Thrace] in the barbarous ages who gave his horses,
men for food. If I knew some rich professor who was inclined to spend
money in the investigation of a curious fact, I would advise him to
set apart a sum for putting horses on a meat diet, from sire to son,
gradually increasing the quantity; and I would boldly warrant that in
the course of successive generations the canines would become so large
as to impede the entrance of the bit into the mouth, and, moreover,
would make it rather a ticklish office for the groom to place it there.
But let us set aside the teeth the horse might possibly have, in order
to examine those it has already. There are six incisors in each jaw;
these are long and rather projecting teeth, by examining which, the
age of the horse can be detected from certain marks which appear in
them from year to year. The molars are flat, square, furrowed with
bars of enamel, marking out more or less distinct crescents; perfectly
constructed, in short, for chewing hay and oats. Nevertheless, I should
never be surprised to see the enamel crescents become sharp-cutting
in our rich professor's stable; so skillful is the unseen Architect
who created animals, in altering the house when the tenant changes his
habits.
ORDER 8. _Ruminantia (ruminants)._
I shall retain through life a pleasant recollection of the
_ruminants_. Through them I obtained the first prize for natural
history which was ever given in France to the pupils of the learned
university. It is thirty years ago since this happened, and I own,
without any false modesty, that even now the word _ruminant_ rings
very agreeably in my ear. It reminds me of one of the proudest moments
of my life, of the honor done to me by the illustrious Geoffroy St.
Hilaire, when he called me, a little college urchin, up to him, that
he might have a nearer view, as he said, of the baby-professor who had
spoken so well on ruminants. Yes, it is more than thirty years ago, for
alas! it was in 1831. There needed no less an event, as I have told
you before, than the revolution of 1830 in France to induce the big-wigs
of education to sacrifice two hours per week in one class to the study
of natural history. Yes, my dear child, it is only that short time ago
since natural history became one of the subjects of study in French
colleges; and the gray-haired men of the present day finished their
education, as it is called, without having learnt a single word of
what I am now taking the trouble to teach you, a mere child. You see
you have come into the world just at the right time, and will be able
to instruct others in your turn. But before giving lessons to other
people you must first finish learning your own. Forgive me this
involuntary reference to a happy time when I was not much more rational
than you are. And now, let us return to our ruminants--those dear,
good beasts, the nourishing fathers of the human race.
LETTER XXXII.
MAMMALIA--_continued_.
ORDER 8. _Ruminants--continued_.
Every created thing has an appointed part to perform; but there are
some mysterious parts of which we cannot understand the drift. That
of the ruminants, however, is so clearly marked out, that we detect
it at a glance.
To qualify myself for supplying your young mind with the food I am
going to offer it to-day, I have been obliged, my dear child, to browse
in a good many books of which you could have understood but little
yourself; and I have been forced to ruminate a long time upon what I
have read, and to digest it slowly in my head, which I may say, without
vanity, is of larger capacity than yours; no great wonder at my age.
Now, if I have succeeded in my undertaking, you will benefit by all
the work which has been going on in my mind for the purpose of feeding
yours without over-fatigue to it; and I shall almost have the right
to say that its nourishment has been derived from me. My lamp could
tell you what it has sometimes cost me to supply a single page which
might instruct, without repelling you.
Now, this is precisely what the _ruminant_ does. The part he has
to perform is to collect in the meadows a sort of food, which would
disgust less well-organized stomachs than his own, to work it well up
within him, and to give it back in a more palatable and less
indigestible form. The little flesh-eaters (_carnivora_) come
afterwards to the feast, and the feast is himself!
The whole history, then, of the ruminant is to be read in his stomach.
His real office is to digest, and in fact he devotes the best hours
of his days to the perfecting of that beneficent labor, on which the
life of so many weak stomachs depends. Have you ever amused yourself
by watching a large ox lying down in a meadow? Long after he has
finished grazing, his jaw continues to work, turning round and round
like the grindstone of a painter when he is rubbing down his colors.
Look, and you will see that he will remain there for hours together,
motionless and contemplative, absorbed in this incomprehensible
mastication, rolling about in his throat from time to time some
invisible food. Do not laugh at him, however. As you sec him there he
is performing his part in life, he is _ruminating_.
To ruminate is to chew over again what has been already swallowed;
and, however droll this may seem to you, it is the business which all
ruminants are born to. You remember the monkey's pouch, which serves
him as a larder, whence he takes out his provisions as he wants to
eat. The ruminant has an immense pouch of the same kind, into which,
while he is grazing, he hastily conveys large masses of half-bitten
grass. You probably think he is eating when he has his head down in
the grass; but you are mistaken. This is only a preparatory work; he
is hastily heaping up in his larder the food he intends to eat
by-and-by; only his larder, instead of being, like the monkey's, in
his cheeks, where, indeed, there would not have been half room enough
for those great bundles he tucks in, is in the middle of his body,
close to the extremity of the oesophagus, whose lower wall, being slit
at that part, becomes an imperfectly secure tube, ready to burst open
under pressure, and allow the food to escape between the edges of the
slit; these, otherwise, remaining naturally closed. As soon as the
large bundles of grass come to this part, they press against the walls
of the tube, which they by this means separate, and fall into the
provision-pouch, which bears the name of paunch, or grass-pocket, in
fact. As soon as the paunch is well filled, and the animal sure of his
dinner, he lies down in some quiet corner, where he proceeds gravely
with the important act, which is the real object of his existence. A
little below the entrance to the paunch, and communicating both with
it and the canal of the oesophagus, is a second receptacle, which old
French naturalists, not being much acquainted with Greek, named the
_cap_, on account of its fancied resemblance to the caps worn on
the head, and which we call 'king's hood' or 'honey-comb bag.' This
second stomach now contracts (at least so it is supposed), and thus
retains, as if with a closed fist, a portion of the grass accumulated
in the paunch: of this it forms a pellet, which it sends back into the
oesophagus, and the oesophagus, by continued contractions from below
upwards, returns it to the mouth, where at last the grassy lump is
chewed in good earnest, and to some purpose. There is no necessity for
hurry; the ruminant has no other business on the face of the earth but
this, and thus hour after hour passes away, the food pellets rising
one after another to the onslaught of the teeth. Nor do they go back
again until they have been reduced by long mastication into an almost
liquid paste, which glides through the oesophagus without forcing open
the slit, and falls straight into a third pouch, called by old Frenchmen
the _leaf_, on account of certain large folds, some what like the leaves
of a book, which line the interior; and known to us as the _manyplies_.
From this stomach, No. 3, this grass-pap passes into a fourth and last
bag, which is the real stomach, and where the final work of digestion is
accomplished. This fourth pouch also has a pretty little name of the
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