The Life of the Fly
by
J. Henri Fabre
Part 4 out of 5
taught me that an obligation rests upon whoever wields the pen: he
must have something to say that is capable of interesting us. When
the subject comes within the scope of natural science, the interest
is nearly always assured; the difficulty, the great difficulty, is
to prune it of its thorns and to present it under a prepossessing
aspect. Truth, they say, rises naked from a well. Agreed; but
admit that she is all the better for being decently clothed. She
craves, if not the gaudy furbelows borrowed from rhetoric's
wardrobe, at least a vine leaf. The geometers alone have the right
to refuse her that modest garment; in theorems, plainness suffices.
The others, especially the naturalist, are in duty bound to drape a
gauze tunic more or less elegantly around her waist.
Suppose I say: 'Baptiste, give me my slippers.'
I am expressing myself in plain language, a little poor in
variants. I know exactly what I am saying and my speech is
understood.
Others--and they are numerous--contend that this rudimentary method
is the best in all things. They talk science to their readers as
they might talk slippers to Baptiste. Kaffir syntax does not shock
them. Do not speak to them of the value of a well selected term,
set down in its right place, still less of a lilting construction,
sounding rather well. Childish nonsense they call all that; the
fiddling of a short sighted mind!
Perhaps they are right: the Baptiste idiom is a great economizer of
time and trouble. This advantage does not tempt me; it seems to me
that an idea stands out better if expressed in lucid language, with
sober imagery. A suitable phrase, placed in its correct position
and saying without fuss the things we want to say, necessitates a
choice, an often laborious choice. There are drab words, the
commonplaces of colloquial speech; and there are, so to speak,
colored words, which may be compared with the brushstrokes strewing
patches of light over the gray background of a painting. How are
we to find those picturesque words, those striking features which
arrest the attention? How are we to group them into a language
heedful of syntax and not displeasing to the ear?
I was taught nothing of this art. For that matter, is it ever
taught in the schools? I greatly doubt it. If the fire that runs
through our veins, if inspiration do not come to our aid, we shall
flutter the pages of the thesaurus in vain: the word for which we
seek will refuse to come. Then to what masters shall we have
recourse to quicken and develop the humble germ that is latent
within us? To books.
As a boy, I was always an ardent reader; but the niceties of a
well-balanced style hardly interested me: I did not understand
them. A good deal later, when close upon fifteen, I began vaguely
to see that words have a physiognomy of their own. Some pleased me
better than others by the distinctness of their meaning and the
resonance of their rhythm; they produced a clearer image in my
mind; after their fashion, they gave me a picture of the object
described. Colored by its adjective and vivified by its verb, the
name became a living reality: what it said I saw. And thus,
gradually, was the magic of words revealed to me, when the chances
of, my undirected reading placed a few easy standard pages in my
way.
CHAPTER XIII MATHEMATICAL MEMORIES: MY LITTLE TABLE
It is time to start our analytical geometry. He can come now, my
partner, the mathematician: I think I shall understand what he
says. I have already run through my book and noticed that our
subject, whose beautiful precision makes work a recreation,
bristles with no very serious difficulties.
We begin in my room, in front of a blackboard. After a few
evenings, prolonged into the peaceful watches of the night, I
become aware, to my great surprise, that my teacher, the past
master in those hieroglyphics, is really, more often than not, my
pupil. He does not see the combinations of the abscissas and
ordinates very clearly. I make bold to take the chalk in hand
myself, to seize the rudder of our algebraical boat. I comment on
the book, interpret it in my own fashion, expound the text, sound
the reefs until daylight comes and leads us to the haven of the
solution. Besides, the logic is so irresistible, it is all such
easy going and so lucid that often one seems to be remembering
rather than learning.
And so we proceed, with our positions reversed. I dig into the
hard rock, crumble it, loosen it until I make room for thought to
penetrate. My comrade--I can now allow myself to speak of him on
equal terms--my comrade listens, suggests objections, raises
difficulties which we try to solve in unison. The two combined
levers, inserted in the fissure, end by shaking and overturning the
rocky mass.
I no longer see in the corner of the quartermaster's eye the leery
droop that greeted me at the start. Cordial frankness now reigns,
the infectious high spirits imparted by success. Little by little,
dawn breaks, very misty as yet, but laden with promises. We are
both greatly amazed; and my share in the satisfaction is a double
one, for he sees twice over who makes others see. Thus do we pass
half the night, in delightful hours. We cease when sleep begins to
weigh too heavily on our eyelids.
When my comrade returns to his room, does he sleep, careless for
the moment of the shifting scene which we have conjured up? He
confesses to me that he sleeps soundly. This advantage I do not
possess. It is not in my power to pass the sponge over my poor
brain even as I pass it over the blackboard. The network of ideas
remains and forms as it were a moving cobweb in which repose
wriggles and tosses, incapable of finding a stable equilibrium.
When sleep does come at last, it is often but a state of somnolence
which, far from suspending the activity of the mind, actually
maintains and quickens it more than waking would. During this
torpor, in which night has not yet closed upon the brain, I
sometimes solve mathematical difficulties with which I struggled
unsuccessfully the day before. A brilliant beacon, of which I am
hardly conscious, flares in my brain. Then I jump out of bed,
light my lamp again and hasten to jot down my solutions, the
recollection of which I should have lost on awakening. Like
lightning flashes, those gleams vanish as suddenly as they appear.
Whence do they come? Probably from a habit which I acquired very
early in life: to have food always there for my mind, to pour the
never failing oil constantly into the lamp of thought. Would you
succeed in the things of the mind? The infallible method is to be
always thinking of them. This method I practiced more sedulously
than my comrade; and hence, no doubt, arose the interchange of
positions, the disciple turned into the master. It was not,
however, an overwhelming infatuation, a painful obsession; it was
rather a recreation, almost a poetic feast. As our great lyric
writer put it in the preface to his volume, Les Rayons et les
ombres: 'Mathematics play their part in art as well as in science.
There is algebra in astronomy: astronomy is akin to poetry; there
is algebra in music: music is akin to poetry.'
Is this poetic exaggeration? Surely not: Victor Hugo spoke truly.
Algebra, the poem of order, has magnificent flights. I look upon
its formulae, its strophes as superb, without feeling at all
astonished when others do not agree. My colleague's satirical look
came back when I was imprudent enough to confide my
extrageometrical raptures to his ears: 'Nonsense,' said he, 'pure
stuff and nonsense! Let's get on with our tangents.'
The quartermaster was right: the strict severity of our approaching
examination allowed of no such dreamer's outbursts. Was I, on my
side, very wrong? To warm chill calculation by the fire of the
ideal, to lift one's thought above mere formulae, to brighten the
caverns of the abstract with a spark of life: was this not to ease
the effort of penetrating the unknown? Where my comrade plodded
on, scorning my viaticum, I performed a journey of pleasure. If I
had to lean on the rude staff of algebra, I had for my guide that
voice within me, urging me to lofty flights. Study became a joy.
It became still more interesting when, after the angularities of a
combination of straight lines, I learnt to portray the graces of a
curve. How many properties were there of which the compass knew
nothing, how many cunning laws lay contained in embryo within an
equation, the mysterious nut which must be artistically cracked to
extract the rich kernel, the theorem! Take this or that term, place
the + sign before it and forthwith you have the ellipse, the
trajectory of the planets, with its two friendly foci, transmitting
pairs of vectors whose sum is constant; substitute the--sign and
you have the hyperbola with the antagonistic foci, the desperate
curve that dives into space with infinite tentacles, approaching
nearer and nearer to straight lines, the asymptotes, but never
succeeding in meeting them. Suppress that term and you have the
parabola, which vainly seeks in infinity its lost second focus; you
have the trajectory of the bombshell; you have the path of certain
comets which come one day to visit our sun and then flee to depths
whence they never return. Is it not wonderful thus to formulate
the orbit of the worlds? I thought so then and I think so still.
After fifteen months of this exercise, we went up together for our
examination at Montpellier; and both of us received our degrees as
bachelors of mathematical science. My companion was a wreck: I, on
the other hand, had refreshed myself with analytical geometry.
Utterly worn out by his course of conic sections, my chum declares
that he has had enough. In vain I hold out the glittering prospect
of a new degree, that of licentiate of mathematical science, which
would lead us to the splendors of the higher mathematics and
initiate us into the mechanics of the heavens: I cannot prevail
upon him, cannot make him share my audacity. He calls it a mad
scheme, which will exhaust us and come to nothing. Without the
advice of an experienced pilot, with no other compass than a book,
which is not always very clear, because of its laconic adherence to
set terms, our poor bark is bound to be wrecked on the first reef.
One might as well put out to sea in a nutshell and defy the billows
of the vasty deep. He does not use these actual words, but his
gloomy estimate of the extreme difficulties to be encountered is
enough to explain his refusal. I am quite free to go and break my
neck in far countries; he is more prudent and will not follow me.
I suspect another reason, which the deserter does not confess. He
has obtained the title needed for his plans. What does he care for
the rest? Is it worth while to sit up late at night and wear one's
self out in toil for the mere pleasure of learning? He must be a
madman who, without the lure of profit, lends an ear to the
blandishments of knowledge. Let us retreat into our shell, close
our lid to the importunities of the light and lead the life of a
mussel. There lies the secret of happiness.
This philosophy is not mine. My curiosity sees in a stage
accomplished no more than the preparation for a new stage towards
the retreating unknown. My partner, therefore. leaves me.
Henceforth, I am alone, alone and wretched. There is no one left
with whom I can sit up and thresh the subject out in exhilarating
discussion. There is no one near me to understand me, no one who
can even passively oppose his ideas to mine and take part in the
conflict whence the light will spring, even as a spark is born of
the concussion of two flints. When a difficulty arises, steep as a
cliff, there is no friendly shoulder to support me in my attempt to
climb it. Alone, I have to cling to the roughness of the jagged
rock, to fall, often, and pick myself up, covered with bruises, and
renew the assault; alone, I must give my shout of triumph, without
the least echo of encouragement, when, reaching the summit and
broken in the effort, I am at last allowed to see a little way
beyond.
My mathematical campaign will cost me much stubborn thought: I am
aware of this after the first few lines of my book. I am entering
upon the domain of the abstract, rough ground that can only be
cleared by the insistent plow of reflection. The blackboard,
excellent for the curves of analytical geometry studied in my
friend's company, is now neglected. I prefer the exercise book, a
quire of paper bound in a cover. With this confidant, which allows
one to remain seated and rests the muscles of the legs, I can
commune nightly under my lampshade, until a late hour, and keep
going the forge of thought wherein the intractable problem is
softened and hammered into shape.
My study table, the size of a pocket handkerchief, occupied on the
right by the ink stand--a penny bottle--and on the left by the open
exercise book, gives me just the room which I need to wield the
pen. I love that little piece of furniture, one of the first
acquisitions of my early married life. It is easily moved where
you wish: in front of the window, when the sky is cloudy; into the
discreet light of a corner, when the sun is troublesome. In
winter, it allows you to come close to the hearth, where a log is
blazing.
Poor little walnut board, I have been faithful to you for half a
century and more. Ink-stained, cut and scarred with the penknife,
you lend your support today to my prose as you once did to my
equations. This variation in employment leaves you indifferent;
your patient back extends the same welcome to the formulae of
algebra and the formula of thought. I cannot boast this placidity;
I find that the change has not increased my peace of mind; hunting
for ideas troubles the brain even more than hunting for the roots
of an equation.
You would never recognize me, little friend, if you could give a
glance at my gray mane. Where is the cheerful face of former days,
bright with enthusiasm and hope? I have aged, I have aged. And
you, what a falling off, since you came to me from the dealer's,
gleaming and polished and smelling so good with your beeswax! Like
your master, you have wrinkles, often my work, I admit; for how
many times, in my impatience, have I not dug my pen into you, when,
after its dip in the muddy inkpot, the nib refused to write
decently!
One of your corners is broken off; the boards are beginning to come
loose. Inside you, I hear, from time to time, the plane of the
death-watch, who despoils old furniture. From year to year, new
galleries are excavated, endangering your solidity. The old ones
show on the outside in the shape of tiny round holes. A stranger
has seized upon the latter, excellent quarters, obtained without
trouble. I see the impudent intruder run nimbly under my elbow and
penetrate forthwith into the tunnel abandoned by the death-watch.
She is after game, this slender huntress, clad in black, busy
collecting wood lice for her grubs. A whole nation is devouring
you, you old table; I am writing on a swarm of insects! No support
could be more appropriate to my entomological notes.
What will become of you when your master is gone? Will you be
knocked down for a franc, when the family come to apportion my poor
spoils? Will you be turned into a stand for the pitcher beside the
kitchen sink? Will you be the plank on which the cabbages are
shredded? Or will my children, on the contrary, agree and say:
'Let us preserve the relic. It was where he toiled so hard to
teach himself and make himself capable of teaching others; it was
where he so long consumed his strength to find food for us when we
were little. Let us keep the sacred plank.'
I dare not believe in such a future for you. You will pass into
strange hands, O my old friend; you will become a bedside table,
laden with bowl after bowl of linseed tea, until, decrepit, rickety
and broken down, you are chopped up to feed the flames for a brief
moment under the simmering saucepan. You will vanish in smoke to
join my labors in that other smoke, oblivion, the ultimate resting
place of our vain agitations.
But let us return, little table, to our young days; those of your
shining varnish and of my fond illusions. It is Sunday, the day of
rest, that is to say, of continuous work, uninterrupted by my
duties in the school. I greatly prefer Thursday, which is not a
general holiday and more propitious to studious calm. Such as it
is, for all its distractions, the Lord's day gives me a certain
leisure. Let us make the most of it. There are fifty-two Sundays
in the year, making a total that is almost equivalent to the long
vacation.
It so happens that I have a glorious question to wrestle with
today; that of Kepler's three laws, which, when explored by the
calculus, are to show me the fundamental mechanism of the heavenly
bodies. One of them says: 'The area swept out in a given time by
the radius vector of the path of a planet is proportional to the
time taken.'
From this I have to deduce that the force which confines the planet
to its orbit is directed towards the sun. Gently entreated by the
differential and integral calculus, already the formula is
beginning to voice itself. My concentration redoubles, my mind is
set upon seizing the radiant dawn of truth.
Suddenly, in the distance, br-r-r-rum! Br-r-r-rum! Br-r-r-rum! The
noise comes nearer, grows louder. Woe upon me! And plague take the
Pagoda!
Let me explain. I live in a suburb, at the beginning of the Pernes
Road, far from the tumult of the town [of Carpentras where Fabre
was a master at the college]. Twenty yards in front of my house,
some pleasure gardens have been opened, bearing a signboard
inscribed, 'The Pagoda.' Here, on Sunday afternoons, the lads and
lasses from the neighboring farms come to disport themselves in
country dances. To attract custom and push the sale of
refreshments, the proprietor of the ball ends the Sunday hop with a
tombola. Two hours beforehand, he has the prizes carried along the
public roads, preceded by fifes and drums. From a beribboned pole,
borne by a stalwart fellow in a red sash, dangle a plated goblet, a
handkerchief of Lyons silk, a pair of candlesticks and some packets
of cigars. Who would not enter the pleasure gardens, with such a
bait?
'Br-r-r-rum! Br-r-r-rum! Br-r-r-rum!' goes the procession.
It comes just under my window, wheels to the right and marches into
the establishment, a huge wooden booth, hung with evergreens. And
now, if you dislike noise, flee, flee as far as you can. Until
nightfall, the ophicleides will bellow, the fifes tootle and the
cornets bray. How would you deduce the steps of Kepler's laws to
the accompaniment of that noisy orchestra! It is enough to drive
one mad. Let us be off with all speed.
A mile away, I know a flinty waste beloved of the wheatear and the
locust. Here reigns perfect calm; moreover, there are some clumps
of evergreen oak which will lend me their scanty shade. I take my
book, a few sheets of paper and a pencil and fly to this solitude.
What beauteous silence, what exquisite quiet! But the sun is
overwhelming, under the meager cover of the bushes. Cheerily, my
lad! Have at your Kepler's laws in the company of the blue-winged
locusts. You will return home with your problems solved, but with
a blistered skin. An overdose of sun in the neck shall be the
outcome of grasping the law of the areas. One thing makes up for
another.
During the rest of the week, I have my Thursdays and the evenings,
which I employ in study until I drop with sleep. All told I have
no lack of time, despite the drudgery of my college ties. The
great thing is not to be discouraged by the unavoidable
difficulties encountered at the outset. I lose my way easily in
that dense forest overgrown with creepers that have to be cut away
with the axe to obtain a clearing. A fortunate turn or two; and I
once more know where I am. I lose my way again. The stubborn axe
makes its opening without always letting in sufficient light.
The book is just a book, that is to say, a set text, saying not a
word more than it is obliged to, exceedingly learned, I admit, but,
alas, often obscure! The author, it seems, wrote it for himself.
He understood; therefore others must. Poor beginners, left to
yourselves, you manage as best you can! For you, there shall be no
retracing of steps in order to tackle the difficulty in another
way; no circuit easing the arduous road and preparing the passage;
no supplementary aperture to admit a glimmer of daylight.
Incomparably inferior to the spoken word, which begins again with
fresh methods of attack and is ready to vary the paths that lead to
the open, the book says what it says and nothing more. Having
finished its demonstration, whether you understand or no, the
oracle is inexorably dumb. You reread the text and ponder it
obstinately; you pass and repass your shuttle through the woof of
figures. Useless efforts all: the darkness continues. What would
be needed to supply the illuminating ray? Often enough, a trifle,
a mere word; and that word the book will not speak.
Happy is he who is guided by a master's teaching! His progress does
not know the misery of those wearisome breakdowns. What was I to
do before the disheartening wall that every now and then rose up
and barred my road? I followed d'Alembert's precept in his advice
to young mathematical students: 'Have faith and go ahead,' said the
great geometrician.
Faith I had; and I went on pluckily. And it was well for me that I
did, for I often found behind the wall the enlightenment which I
was seeking in front of it. Giving up the bad patch as hopeless, I
would go on and, after I had left it behind, discover the dynamite
capable of blasting it. 'Twas a tiny grain at first, an
insignificant ball rolling and increasing as it went. From one
slope to the other of the theorems, it grew to a heavy mass; and
the mass became a mighty projectile which, flung backwards and
retracing its course, split the darkness and spread it into one
vast sheet of light.
D'Alembert's precept is good and very good, provided you do not
abuse it. Too much precipitation in turning over the intractable
page might expose you to many a disappointment. You must have
fought the difficulty tooth and nail before abandoning it. This
rough skirmishing leads to intellectual vigor.
Twelve months of meditation in the company of my little table at
last won me my degree as a licentiate of mathematical science; and
I was now qualified to perform, half a century later, the eminently
lucrative functions of an inspector of Spiders' webs!
CHAPTER XIV THE BLUEBOTTLE: THE LAYING
To purge the earth of death's impurities and cause deceased animal
matter to be once more numbered among the treasures of life there
are hosts of sausage queens, including, in our part of the world,
the bluebottle (Calliphora vomitaria, LIN.) and the checkered flesh
fly (Sarcophaga carnaria, LIN.). Every one knows the first, the
big, dark-blue fly who, after effecting her designs in the ill-
watched meat safe, settles on our window panes and keeps up a
solemn buzzing, anxious to be off in the sun and ripen a fresh
emission of germs. How does she lay her eggs, the origin of the
loathsome maggot that battens poisonously on our provisions,
whether of game or butcher's meat? What are her stratagems and how
can we foil them? This is what I propose to investigate.
The bluebottle frequents our homes during autumn and a part of
winter, until the cold becomes severe; but her appearance in the
fields dates back much earlier. On the first fine day in February,
we shall see her warming herself, chillily, against the sunny
walls. In April, I notice her in considerable numbers on the
laurestinus. It is here that she seems to pair, while sipping the
sugary exudations of the small white flowers. The whole of the
summer season is spent out of doors, in brief flights from one
refreshment bar to the next. When autumn comes, with its game, she
makes her way into our houses and remains until the hard frosts.
This suits my stay-at-home habits and especially my legs, which are
bending under the weight of years. I need not run after the
subjects of my present study; they call on me. Besides, I have
vigilant assistants. The household knows of my plans. Every one
brings me, in a little screw of paper, the noisy visitor just
captured against the panes.
Thus do I fill my vivarium, which consists of a large, bell-shaped
cage of wire gauze, standing in an earthenware pan full of sand. A
mug containing honey is the dining room of the establishment. Here
the captives come to recruit themselves in their hours of leisure.
To occupy their maternal cares, I employ small birds--chaffinches,
linnets, sparrows--brought down, in the enclosure, by my son's gun.
I have just served up a Linnet shot two days ago. I next place in
the cage a bluebottle, one only, to avoid confusion. Her fat belly
proclaims the advent of a laying time. An hour later, when the
excitement of being put in prison is allayed, my captive is in
labor. With eager, jerky steps, she explores the morsel of game,
goes from the head to the tail, returns from the tail to the head,
repeats the action several times and at last settles near an eye, a
dimmed eye sunk into its socket.
The ovipositor bends at a right angle and dives into the junction
of the beak, straight down to the root. Then the eggs are emitted
for nearly half an hour. The layer, utterly absorbed in her
serious business, remains stationary and impassive and is easily
observed through my lens. A movement on my part would doubtless
scare her; but my restful presence gives her no anxiety. I am
nothing to her.
The discharge does not go on continuously until the ovaries are
exhausted; it is intermittent and performed in so many packets.
Several times over, the fly leaves the bird's beak and comes to
take a rest upon the wire gauze, where she brushes her hind legs
one against the other. In particular, before using it again, she
cleans, smoothes and polishes her laying tool, the probe that
places the eggs. Then, feeling her womb still teeming, she returns
to the same spot at the joint of the beak. The delivery is
resumed, to cease presently and then begin anew. A couple of hours
are thus spent in alternate standing near the eye and resting on
the wire gauze.
At last, it is over. The fly does not go back to the bird, a proof
that her ovaries are exhausted. The next day, she is dead. The
eggs are dabbed in a continuous layer, at the entrance to the
throat, at the root of the tongue, on the membrane of the palate.
Their number appears considerable; the whole inside of the gullet
is white with them. I fix a little wooden prop between the two
mandibles of the beak, to keep them open and enable me to see what
happens.
I learn in this way that the hatching takes place in a couple of
days. As soon as they are born, the young vermin, a swarming mass,
leave the place where they are and disappear down the throat. To
inquire further into the work is useless for the moment. We shall
learn more about it later, under conditions that make examination
easier.
The beak of the bird invaded was closed at the start, as far as the
natural contact of the mandibles allowed. There remained a narrow
slit at the base, sufficient at most to admit the passage of a
horsehair. It was through this that the laying was performed.
Lengthening her ovipositor like a telescope, the mother inserted
the point of her implement, a point slightly hardened with a horny
armor. The fineness of the probe equals the fineness of the
aperture. But, if the beak were entirely closed, where would the
eggs be laid then?
With a tied thread, I keep the two mandibles in absolute contact;
and I place a second bluebottle in the presence of the linnet,
which the colonists have already entered by the beak. This time,
the laying takes place on one of the eyes, between the lid and the
eyeball. At the hatching, which again occurs a couple of days
later, the grubs make their way into the fleshy depths of the
socket. The eyes and the beak, therefore, form the two chief
entrances into feathered game.
There are others; and these are the wounds. I cover the linnet's
head with a paper hood which will prevent invasion through the beak
and eyes. I serve it, under the wire gauze bell, to a third egg
layer. The bird has been struck by a shot in the breast, but the
sore is not bleeding: no outer stain marks the injured spot.
Moreover, I am careful to arrange the feathers, to smooth them with
a hair pencil, so that the bird looks quite smart and has every
appearance of being untouched.
The fly is soon there. She inspects the linnet from end to end;
with her front tarsi she fumbles at the breast and belly. It is a
sort of auscultation by sense of touch. The insect becomes aware
of what is under the feathers by the manner in which these react.
If scent comes to her assistance, it can only be very slightly, for
the game is not yet high. The wound is soon found. No drop of
blood is near it, for it is closed by a plug of down rammed into it
by the shot. The fly takes up her position without separating the
feathers or uncovering the wound. She remains here for two hours
without stirring, motionless, with her abdomen concealed beneath
the plumage. My eager curiosity does not distract her from her
business for a moment.
When she has finished, I take her place. There is nothing either
on the skin or at the mouth of the wound. I have to withdraw the
downy plug and dig to some depth before discovering the eggs. The
ovipositor has therefore lengthened its extensible tube and pushed
beyond the feather stopper driven in by the lead. The eggs are in
one packet; they number about three hundred.
When the beak and eyes are rendered inaccessible, when the body,
moreover, has no wounds, the laying still takes place, but, this
time, in a hesitating and niggardly fashion. I pluck the bird
completely, the better to watch what happens; also, I cover the
head with a paper hood to close the usual means of access. For a
long time, with jerky steps, the mother explores the body in every
direction; she takes her stand by preference on the head, which she
sounds by tapping on it with her front tarsi. She knows that the
openings which she needs are there, under the paper; but she also
knows how frail are her grubs, how powerless to pierce their way
through the strange obstacle which stops her as well and interferes
with the work of her ovipositor. The cowl inspires her with
profound distrust. Despite the tempting bait of the veiled head,
not an egg is laid on the wrapper, slight though it may be.
Weary of vain attempts to compass this obstacle, the Fly at last
decides in favor of other points, but not on the breast, belly or
back, where the hide would seem too tough and the light too
intrusive. She needs dark hiding places, corners where the skin is
very delicate. The spots chosen are the cavity of the axilla,
corresponding with our armpit, and the crease where the thigh joins
the belly. Eggs are laid in both places, but not many, showing
that the groin and the axilla are adopted only reluctantly and for
lack of a better spot.
With an unplucked bird, also hooded, the same experiment failed:
the feathers prevent the fly from slipping into those deep places.
Let us add, in conclusion, that, on a skinned bird, or simply on a
piece of butcher's meat, the laying is effected on any part
whatever, provided that it be dark. The gloomiest corners are the
favorite ones.
It follows from all this that, to lay the eggs, the Bluebottle
picks out either naked wounds or else the mucous membranes of the
mouth or eyes, which are not protected by a skin of any thickness.
She also needs darkness. We shall see the reasons for her
preference later on.
The perfect efficiency of the paper bag, which prevents the inroads
of the worms through the eye sockets or the beak, suggests a
similar experiment with the whole bird. It is a matter of wrapping
the body in a sort of artificial skin which will be as discouraging
to the fly as the natural skin. Linnets, some with deep wounds,
others almost intact, are placed one by one in paper envelopes
similar to those in which the nursery gardener keeps his seeds,
envelopes just folded, without being stuck. The paper is quite
ordinary and of average thickness. Torn pieces of newspaper serve
the purpose.
These sheaths with the corpses inside them are freely exposed to
the air, on the table in my study, where they are visited,
according to the time of day, in dense shade and in bright
sunlight. Attracted by the effluvia from the dead meat, the
bluebottles haunt my laboratory, the windows of which are always
open. I see them daily alighting on the envelopes and very busily
exploring them, apprised of the contents by the gamy smell. Their
incessant coming and going is a sign of intense cupidity; and yet
none of them decides to lay on the bags. They do not even attempt
to slide their ovipositor through the slits of the folds. The
favorable season passes and not an egg is laid on the tempting
wrappers. All the mothers abstain, judging the slender obstacle of
the paper to be more than the vermin will be able to overcome.
This caution on the fly's part does not at all surprise me:
motherhood everywhere has gleams of great perspicacity. What does
astonish me is the following result. The parcels containing the
linnets are left for a whole year uncovered on the table; they
remain there for a second year and a third. I inspect the contents
from time to time. The little birds are intact, with unrumpled
feathers, free from smell, dry and light, like mummies. They have
become not decomposed, but mummified.
I expected to see them putrefying, running into sanies, like
corpses left to rot in the open air. On the contrary, the birds
have dried and hardened, without undergoing any change. What did
they want for their putrefaction? Simply the intervention of the
fly. The maggot, therefore, is the primary cause of dissolution
after death; it is, above all, the putrefactive chemist.
A conclusion not devoid of value may be drawn from my paper game
bags. In our markets, especially in those of the South, the game
is hung unprotected from the hooks on the stalls. Larks strung up
by the dozen with a wire through their nostrils, thrushes, plovers,
teal, partridges, snipe, in short, all the glories of the spit
which the autumn migration brings us, remain for days and weeks at
the mercy of the flies. The buyer allows himself to be tempted by
a goodly exterior; he makes his purchase and, back at home, just
when the bird is being prepared for roasting, he discovers that the
promised dainty is alive with worms. O horror! There is nothing
for it but to throw the loathsome, verminous thing away.
The bluebottle is the culprit here. Everybody knows it; and nobody
thinks of seriously shaking off her tyranny: not the retailer, nor
the wholesale dealer, nor the killer of the game. What is wanted
to keep the maggots out? Hardly anything: to slip each bird into a
paper sheath. If this precaution were taken at the start, before
the flies arrive, any game would be safe and could be left
indefinitely to attain the degree of ripeness required by the
epicure's palate.
Stuffed with olives and myrtle berries, the Corsican blackbirds are
exquisite eating. We sometimes receive them at Orange, layers of
them, packed in baskets through which the air circulates freely and
each contained in a paper wrapper. They are in a state of perfect
preservation, complying with the most exacting demands of the
kitchen. I congratulate the nameless shipper who conceived the
bright idea of clothing his blackbirds in paper. Will his example
find imitators? I doubt it.
There is, of course, a serious objection to this method of
preservation. In its paper shroud, the article is invisible; it is
not enticing; it does not inform the passer by of its nature and
qualities. There is one resource left which would leave the bird
uncovered: simply to case the head in a paper cap. The head being
the part most threatened, because of the mucus membrane of the
throat and eyes, it would be sufficient, as a rule, to protect the
head, in order to keep off the Flies and to thwart their attempts.
Let us continue to study the bluebottle, while varying our means of
information. A tin, about four inches deep, contains a piece of
butcher's meat. The lid is not put in quite straight and leaves a
narrow slit at one point of its circumference, allowing, at most,
of the passage of a fine needle. When the bait begins to give off
a gamy scent, the mothers come. Singly or in numbers. They are
attracted by the odor which, transmitted through a thin crevice,
hardly reaches my nostrils.
They explore the metal receptacle for some time, seeking an
entrance. Finding naught that enables them to reach the coveted
morsel, they decide to lay their eggs on the tin, just beside the
aperture. Sometimes, when the width of the passage allows of it,
they insert the ovipositor into the tin and lay the eggs inside, on
the very edges of the slit. Whether outside or in, the eggs are
dabbed down in a fairly regular and absolutely white layer. I as
it were shovel them up with a little paper scoop. I thus obtain
all the germs that I require for my experiments, eggs bearing no
trace of the stains which would be inevitable if I had to collect
them on tainted meat.
We have seen the bluebottle refusing to lay her eggs on the paper
bag, notwithstanding the carrion fumes of the Linnet enclosed; yet
now, without hesitation, she lays them on a sheet of metal. Can
the nature of the floor make any difference to her? I replace the
tin lid by a paper cover stretched and pasted over the orifice.
With the point of my knife, I make a narrow slit in this new lid.
That is quite enough: the parent accepts the paper.
What determined her, therefore, is not simply the smell, which can
easily be perceived even through the uncut paper, but, above all,
the crevice, which will provide an entrance for the vermin, hatched
outside, near the narrow passage. The maggots' mother has her own
logic, her prudent foresight. She knows how feeble her wee grubs
will be, how powerless to cut their way through an obstacle of any
resistance; and so, despite the temptation of the smell, she
refrains from laying so long as she finds no entrance through which
the newborn worms can slip unaided.
I wanted to know whether the color, the shininess, the degree of
hardness and other qualities of the obstacle would influence the
decision of a mother obliged to lay her eggs under exceptional
conditions. With this object in view, I employed small jars, each
baited with a bit of butcher's meat. The respective lids were made
of different colored paper, of oilskin, or of some of that tinfoil,
with its gold or coppery sheen, which is used for sealing liqueur
bottles. On not one of these covers did the mothers stop, with any
desire to deposit their eggs; but, from the moment that the knife
had made the narrow slit, all the lids were, sooner or later,
visited and all of them, sooner or later, received the white shower
somewhere near the gash. The look of the obstacle, therefore, does
not count; dull or brilliant, drab or colored: these are details of
no importance; the thing that matters is that there should be a
passage to allow the grubs to enter.
Though hatched outside, at a distance from the coveted morsel, the
newborn worms are well able to find their refectory. As they
release themselves from the egg, without hesitation, so accurate is
their scent, they slip beneath the edge of the ill-joined lid, or
through the passage cut by the knife. Behold them entering upon
their promised land, their reeking paradise.
Eager to arrive, do they drop from the top of the wall? Not they!
Slowly creeping, they make their way down the side of the jar; they
use their fore part, ever in quest of information, as a crutch and
grapnel in one. They reach the meat and at once install themselves
upon it.
Let us continue our investigation, varying the conditions. A large
test-tube, measuring nine inches high, is baited at the bottom with
a lump of butcher's meat. It is closed with wire gauze, whose
meshes, two millimeters wide, do not permit of the fly's passage.
The bluebottle comes to my apparatus, guided by scent rather than
sight. She hastens to the test tube whose contents are veiled
under an opaque cover with the same alacrity as to the open tube.
The invisible attracts her quite as much as the visible.
She stays a while on the lattice of the mouth, inspects it
attentively; but, whether because circumstances have failed to
serve me, or because the wire network inspires her with distrust, I
never saw her dab her eggs upon it for certain. As her evidence
was doubtful, I had recourse to the flesh fly (Sarcophaga
carnaria).
This fly is less finicky in her preparations, she has more faith in
the strength of her worms, which are born ready-formed and
vigorous, and easily shows me what I wish to see. She explores the
trellis-work, chooses a mesh through which she inserts the tip of
her abdomen and, undisturbed by my presence, emits, one after the
other, a certain number of grubs, about ten or so. True, her
visits will be repeated, increasing the family at a rate of which I
am ignorant.
The newborn worms, thanks to a slight viscidity, cling for a moment
to the wire gauze; they swarm, wriggle, release themselves and leap
into the chasm. It is a nine inch drop at least. When this is
done, the mother makes off, knowing for a certainty that her
offspring will shift for themselves. If they fall on the meat,
well and good; if they fall elsewhere, they can reach the morsel by
crawling.
This confidence in the unknown factor of the precipice, with no
indication but that of smell, deserves fuller, investigation. From
what height will the flesh fly dare to let her children drop? I
top the test-tube with another tube, the width of the neck of a
claret bottle. The mouth is closed either with wire gauze, or with
a paper cover with a slight cut in it. Altogether, the apparatus
measures twenty-five inches in height. No matter: the fall is not
serious for the lithe backs of the young grubs; and, in a few days,
the test-tube is filled with larvae, in which it is easy to
recognize the flesh fly's family by the fringed coronet that opens
and shuts at the maggot's stern like the petals of a little flower.
I did not see the mother operating: I was not there at the time;
but there is no doubt possible of her coming nor of the great dive
taken by the family: the contents of the test-tube furnish me with
a duly authenticated certificate.
I admire the leap and, to obtain one better still, I replace the
tube by another, so that the apparatus now stands forty-six inches
high. The column is erected at a spot frequented by flies, in a
dim light. Its mouth, closed with a wire gauze cover, reaches the
level of various other appliances, test-tubes and jars, which are
already stocked or awaiting their colony of vermin. When the
position is well known to the flies, I remove the other tubes and
leave the column, lest the visitors should turn aside to easier
ground.
From time to time, the bluebottle and the flesh fly perch on the
trellis-work, make a short investigation and then decamp.
Throughout the summer season, for three whole months, the apparatus
remains where it is, without the least result: never a worm. What
is the reason? Does the stench of the meat not spread, coming from
that depth? Certainly it spreads: it is unmistakable to my dulled
nostrils and still more so to the nostrils of my children, whom I
call to bear witness. Then why does the flesh fly, who but now was
dropping her grubs from a goodly height, refuse to let them fall
from the top of a column twice as high? Does she fear lest her
worms should be bruised by an excessive drop? There is nothing
about her to point to anxiety aroused by the length of the shaft.
I never see her explore the tube or take its size. She stands on
the trellised orifice; and there the matter ends. Can she be
apprised of the depth of the chasm by the comparative faintness of
the offensive odors that arise from it? Can the sense of smell
measure the distance and judge whether it be acceptable or not?
Perhaps.
The fact remains that, despite the attraction of the scent, the
flesh fly does not expose her worms to disproportionate falls. Can
she know beforehand that, when the chrysalides break, her winged
family, knocking with a sudden flight against the sides of a tall
chimney, will be unable to get out? This foresight would be in
agreement with the rules which order maternal instinct according to
future needs.
But when the fall does not exceed a certain depth, the budding
worms of the flesh fly are dropped without a qualm, as all our
experiments show. This principle has a practical application which
is not without its value in matters of domestic economy. It is as
well that the wonders of entomology should sometimes give us a hint
of commonplace utility.
The usual meat safe is a sort of large cage with a top and bottom
of wood and four wire gauze sides. Hooks fixed into the top are
used whereby to hang pieces which we wish to protect from the
flies. Often, so as to employ the space to the best advantage,
these pieces are simply laid on the floor on the cage. With these
arrangements, are we sure of warding off the fly and her vermin?
Not at all. We may protect ourselves against the Bluebottle, who
is not much inclined to lay her eggs at a distance from the meat;
but there is still the flesh fly, who is more venturesome and goes
more briskly to work and who will slip the grubs through a hole in
the meshes and drop them inside the safe. Agile as they are and
well able to crawl, the worms will easily reach anything on the
floor; the only things secure from their attacks will be the pieces
hanging from the ceiling. It is not in the nature of maggots to
explore the heights, especially if this implies climbing down a
string in addition.
People also use wire gauze dish covers. The trellised dome
protects the contents even less than does the meat safe. The flesh
fly takes no heed of it. She can drop her worms through the meshes
on the covered joint.
Then what are we to do? Nothing could be simpler. We need only
wrap the birds which we wish to preserve--thrushes, partridges,
snipe and so on--in separate paper envelopes; and the same with our
beef and mutton. This defensive armor alone, while leaving ample
room for the air to circulate, makes any invasion by the worms
impossible, even without a cover or a meat safe: not that paper
possesses any special preservative virtues, but solely because it
forms an impenetrable barrier. The Bluebottle carefully refrains
from laying her eggs upon it and the flesh fly from bringing forth
her offspring, both of them knowing that their newborn young are
incapable of piercing the obstacle.
Paper is equally successful in our strife against the Moths, those
plagues of our furs and clothes. To keep away these wholesale
ravages, people generally use camphor, naphthalene, tobacco,
bunches of lavender and other strong-scented remedies. Without
wishing to malign those preservatives, we are bound to admit that
the means employed are none too effective. The smell does very
little to prevent the havoc of the moths.
I would therefore counsel our housewives, instead of all this
chemist's stuff, to use newspapers of a suitable shape and size.
Take whatever you wish to protect--your furs, your flannel or your
clothes--and pack each article carefully in a newspaper, joining
the edges with a double fold, well pinned. If this joining is
properly done, the Moth will never get inside. Since my advice has
been taken and this method employed in my household, the old damage
has never been repeated.
To return to the fly. A piece of meat is hidden in a jar under a
layer of fine, dry sand, a finger's-breadth thick. The jar has a
wide mouth and is left quite open. Let whoever come that will,
attracted by the smell. The Bluebottles are not long in inspecting
what I have prepared for them: they enter the jar, go out and come
back again, inquiring into the invisible thing revealed by its
fragrance. A diligent watch enables me to see them fussing about,
exploring the sandy expanse, tapping it with their feet, sounding
it with their proboscis. I leave the visitors undisturbed for a
fortnight or three weeks. None of them lays any eggs.
This is a repetition of what the paper bag, with its dead bird,
showed me. The flies refuse to lay on the sand, apparently for the
same reasons. The paper was considered an obstacle which the frail
vermin would not be able to overcome. With sand, the case is
worse. Its grittiness would hurt the newborn weaklings, its
dryness would absorb the moisture indispensable to their movements.
Later, when preparing for the metamorphosis, when their strength
has come to them, the grubs will dig the earth quite well and be
able to descend; but, at the start, that would be very dangerous
for them. Knowing these difficulties, the mothers, however greatly
tempted by the smell, abstain from breeding. As a matter of fact,
after long waiting, fearing lest some packets of eggs may have
escaped my attention, I inspect the contents of the jar from top to
bottom. Meat and sand contain neither larvae nor pupae: the whole
is absolutely deserted.
The layer of sand being only a finger's-breadth thick, this
experiment requires certain precautions. The meat may expand a
little, in going bad, and protrude in one or two places. However
small the fleshy eyots that show above the surface, the flies come
to them and breed. Sometimes also the juices oozing from the
putrid meat soak a small extent of the sandy floor. That is enough
for the maggot's first establishment. These causes of failure are
avoided with a layer of sand about an inch thick. Then the
bluebottle, the flesh fly and other flies whose grubs batten on
dead bodies are kept at a proper distance.
In the hope of awakening us to a proper sense of our
insignificance, pulpit orators sometimes make an unfair use of the
grave and its worms. Let us put no faith in their doleful
rhetoric. The chemistry of man's final dissolution is eloquent
enough of our emptiness: there is no need to add imaginary horrors.
The worm of the sepulchre is an invention of cantankerous minds,
incapable of seeing things as they are. Covered by but a few
inches of earth, the dead can sleep their quiet sleep: no fly will
ever come to take advantage of them.
At the surface of the soil, exposed to the air, the hideous
invasion is possible; ay, it is the invariable rule. For the
melting down and remolding of matter, man is no better, corpse for
corpse, than the lowest of the brutes. Then the fly exercises her
rights and deals with us as she does with any ordinary animal
refuse. Nature treats us with magnificent indifference in her
great regenerating factory: placed in her crucibles, animals and
men, beggars and kings are one and all alike. There you have true
equality, the only equality in this world of ours: equality in the
presence of the maggot.
CHAPTER XV THE BLUEBOTTLE: THE GRUB
The larvae of the bluebottle hatch within two days in the warm
weather. Whether inside my apparatus, in direct contact with the
piece of meat, or outside, on the edge of a slit that enables them
to enter, they set to work at once. They do not eat, in the strict
sense of the word, that is to say, they do not tear their food, do
not chew it by means of implements of mastication. Their mouth
parts do not lend themselves to this sort of work. These mouth
parts are two horny spikes, sliding one upon the other, with curved
ends that do not face, thus excluding the possibility of any
function such as seizing and grinding.
The two guttural grapnels serve for walking much rather than for
feeding. The worm plants them alternately in the road traversed
and, by contracting its crupper, advances just that distance. It
carries in its tubular throat the equivalent of our iron tipped
sticks which give support and assist progress.
Thanks to this machinery of the mouth, the maggot not only moves
over the surface, but also easily penetrates the meat: I see it
disappear as though it were dipping into butter. It cuts its way,
levying, as it goes, a preliminary toll, but only of liquid
mouthfuls. Not the smallest solid particle is detached and
swallowed. That is not the maggot's diet. It wants a broth, a
soup, a sort of fluid extract of beef which it prepares itself. As
digestion, after all, merely means liquefaction, we may say,
without being guilty of paradox, that the grub of the bluebottle
digests its food before swallowing it.
With the object of relieving gastric troubles, our manufacturing
chemists scrape the stomachs of the pig and sheep and thus obtain
pepsin, a digestive agent which possesses the property of
liquefying albuminous matters and lean meat in particular. Why
cannot they rasp the stomach of the maggot! They would obtain a
product of the highest quality, for the carnivorous worm also owns
its pepsin, pepsin of a singularly active kind, as the following
experiments will show us.
I divide the white of a hard-boiled egg into tiny cubes and place
them in a little test-tube. On the top of the contents, I sprinkle
the eggs of the bluebottle, eggs free from the least stain, taken
from those laid on the outside of tins baited with meat and not
absolutely shut. A similar test-tube is filled with white of egg,
but receives no germs. Both are closed with a plug of cotton-wool
and left in a dark corner.
In a few days, the tube swarming with newborn vermin contains a
liquid as fluid and transparent as water. Not a drop would remain
in the tube if I turned it upside down. All the white of egg has
disappeared, liquefied. As for the worms, which are already a fair
size, they seem very ill at ease. Deprived of a support whence to
attain the outer air, most of them dive into the broth of their own
making, where they perish by drowning. Others, endowed with
greater vigor, crawl up the glass to the plug and manage to make
their way through the wadding. Their pointed front, armed with
grappling irons, is the nail that penetrates the fibrous mass.
In the other test-tube, standing beside the first and subjected to
the same atmospheric influences, nothing striking has occurred.
The hard-boiled white of egg has retained its dead white color and
its firmness. I find it as I left it. The utmost that I observe
is a few traces of must. The result of this first experiment is
patent: the Bluebottle's grub is the medium that converts
coagulated albumen into a liquid.
The value of chemist's pepsin is estimated by the quantity of hard-
boiled white of egg which a gram of that agent can liquefy. The
mixture has to be exposed in an oven to a temperature of 1400 F.
and also to be frequently shaken. My preparation, in which the
bluebottle's eggs are hatched, is neither shaken nor subjected to
the heat of an oven; everything happens in quietness and under the
thermometric conditions of the surrounding air; nevertheless, in a
few days, the coagulated albumen, treated by the vermin, runs like
water.
The reagent that causes this liquefaction escapes my endeavors to
detect it. The worms must disgorge it in infinitesimal doses,
while the spikes in their throats, which are in continual movement,
emerge a little way from the mouth, reenter and reappear. Those
piston thrusts, those quasi-kisses, are accompanied by the emission
of the solvent: at least, that is how I picture it. The maggot
spits on its food, places on it the wherewithal to make it into
broth. To appraise the quantity of the matter expectorated is
beyond my powers: I observe the result, but do not perceive the
leavening agent.
Well, this result is really astounding, when we consider the
scantiness of the means. No pig's or sheep's pepsin can rival that
of the worm. I have a bottle of pepsin that comes from the School
of Chemistry at Montpellier. I lavishly powder some pieces of
hard-boiled white of egg with the potent drug, just as I did with
the eggs of the Bluebottle. The oven is not brought into play,
neither is distilled water added, nor hydrochloric acid: two
auxiliaries which are recommended. The experiment is conducted in
exactly the same way as that of the tubes with the vermin. The
result is entirely different from what I expected. The white of
egg does not liquefy. It simply becomes moist on the surface; and
even this moisture may come from the pepsin, which is highly
absorbent. Yes, I was right: if the thing were feasible, it would
be an advantage for the chemists to collect their digestive drug
from the stomach of the maggot. The worm, in this case, beats the
pig and the sheep.
The same method is followed for the remaining experiments. I put
the bluebottle's eggs to hatch on a piece of meat and leave the
worms to do their work as they please. The lean tissues, whether
of mutton, beef or pork, no matter which, are not turned into
liquid; they become a pea soup of a clarety brown. The liver, the
lung, the spleen are attacked to better purpose, without, however,
getting beyond the state of a semi-fluid jam, which easily mixes
with water and even appears to dissolve in it. The brains do not
liquefy either: they simply melt into a thin gruel.
On the other hand, fatty substances, such as beef suet, lard and
butter, do not undergo any appreciable change. Moreover, the worms
soon dwindle away, incapable of growing. This sort of food does
not suit them. Why? Apparently because it cannot be liquefied by
the reagent disgorged by the worms. In the same way, ordinary
pepsin does not attack fatty substances; it takes pancreatin to
reduce them to an emulsion. This curious analogy of properties,
positive for albuminous, negative for fatty matter, proclaims the
similarity and perhaps the identity of the dissolvent discharged by
the grubs and the pepsin of the higher animals.
Here is another proof: the usual pepsin does not dissolve the
epidermis, which is a material of a horny nature. That of the
maggots does not dissolve it either. I can easily rear bluebottle
grubs on dead crickets whose bellies I have first opened; but I do
not succeed if the morsel be left intact: the worms are unable to
perforate the succulent paunch; they are stopped by the cuticle, on
which their reagent refuses to act. Or else I give them frogs'
hind legs, stripped of their skin. The flesh turns to broth and
disappears to the bone. If I do not peel the legs, they remain
intact in the midst of the vermin. Their thin skin is sufficient
to protect them.
This failure to act upon the epidermis explains why the bluebottle
at work on the animal declines to lay her eggs on the first part
that comes handy. She needs the delicate membrane of the nostrils,
eyes or throat, or else some wound in which the flesh is laid bare.
No other place suits her, however excellent for flavor and
darkness. At most, finding nothing better when my stratagems
interfere, she persuades herself to dab a few eggs under the axilla
of a plucked bird or in the groin, two points at which the skin is
thinner than elsewhere.
With her maternal foresight, the bluebottle knows to perfection the
choice surfaces, the only ones liable to soften and run under the
influence of the reagent dribbled by the newborn grubs. The
chemistry of the future is familiar to her, though she does not use
it for her own feeding; motherhood, that great inspirer of
instinct, teaches her all about it.
Scrupulous though she be in choosing exactly where to lay her eggs,
the bluebottle does not trouble about the quality of the provisions
intended for her family's consumption. Any dead body suits her
purpose. Redi, the Italian scientist who first exploded the old,
foolish notion of worms begotten of corruption, fed the vermin in
his laboratory with meat of very different kinds. In order to make
his tests the more conclusive, he exaggerated the largess of the
dining hall. The diet was varied with tiger and lion flesh, bear
and leopard, fox and wolf, mutton and beef, horseflesh, donkey
flesh and many others, supplied by the rich menagerie of Florence.
This wastefulness was unnecessary: wolf and mutton are all the same
to an unprejudiced stomach.
A distant disciple of the maggot's biographer, I look at the
problem in a light which Redi never dreamt of. Any flesh of one of
the higher animals suits the fly's family. Will it be the same if
the food supplied be of a lower organism and consist of fish, for
instance, of frog, mollusk, insect, centipede? Will the worms
accept these viands and, above all, can they manage to liquefy
them, which is the first and foremost condition?
I serve a piece of raw whiting. The flesh is white, delicate,
partly translucent, easy for our stomachs to digest and no less
suited to the grub's dissolvent. It turns into an opalescent
fluid, which runs like water. In fact, it liquefies in much the
same way as hard-boiled white of egg. The worms at first wax fat,
as long as the conditions allow of some solid eyots remaining;
then, when foothold fails, threatened with drowning in the too
fluid broth, they creep up the side of the glass, anxious and
restless to be off. They climb to the cotton-wool stopper of the
test-tube and try to bolt through the wadding. Endowed with
stubborn perseverance, nearly all of them decamp in spite of the
obstacle. The test-tube with the white of egg showed me a similar
exodus. Although the fare suits them, as their growth witnesses,
the worms cease feeding and make a point of escaping when death by
drowning is imminent.
With other fish, such as skate and sardines, with the flesh of
frogs and tree frogs, the meat simply dissolves into a porridge.
Hashes of slug, Scolopendra or praying mantis furnish the same
result.
In all these preparations, the dissolving agent of the worms is as
much in evidence as when butcher's meat is employed. Moreover, the
grubs seem satisfied with the queer dish which my curiosity
prescribes for them; they thrive amidst the victuals and undergo
their transformation into pupae.
The conclusion, therefore, is much more general than Redi imagined.
Any meat, no matter whether of a higher or lower order, suits the
bluebottle for the settlement of her family. The carcasses of
furred and feathered animals are the favorite victuals, probably
because of their richness, which allows of plentiful layings; but,
should the occasion demand it, the others are also accepted,
without inconvenience. Any carrion that has lived the life of an
animal comes within the domain of these scavengers.
What is their number to one mother? I have already spoken of a
deposit of three hundred, counted egg by egg. A quite fortuitous
circumstance enabled me to go much farther. In the first week of
January 1905, we experienced a sudden short cold snap of a severity
very exceptional in my part of the country. The thermometer fell
to twelve degrees below zero. While a fierce north wind was raging
and beginning to redden the leaves of the olive trees, came one and
brought me a barn or screech owl, which he had found on the ground,
exposed to the air, not far from my house. My reputation as a
lover of animals made the donor believe that I should be pleased
with his gift.
I was, as a matter of fact, but for reasons whereof the finder
certainly never dreamt. The owl was untouched, with trim feathers
and not the least wound that showed. Perhaps he had died of cold.
What made me gratefully accept the present was exactly that which
would have inclined anyone but myself to refuse it. The owl's
eyes, glazed in death, were hidden under a thick mass of eggs,
which I recognized as a bluebottle's. Similar masses occupied the
vicinity of the nostrils. If I wanted maggots, here, of a
certainty, was a richer crop than I had ever beheld.
I place the corpse on the sand of a pan, with a wire gauze cover,
and leave events to take their course. The laboratory in which I
install my bird is none other than my study. It is as cold in
there, or nearly, as outside, so much so that the water in the
aquarium in which I used to rear caddis worms has frozen into a
solid block of ice. Under these conditions of temperature, the
owl's eyes keep their white veil of germs unchanged. Nothing
stirs, nothing swarms. Weary of waiting, I pay no more attention
to the carcass; I leave the future to decide whether the cold has
exterminated the fly's family or not.
Before the end of March, the packets of eggs have disappeared, I
know not how long. The bird, for that matter, seems to be intact.
On the ventral surface, which is turned to the air, the feathers
keep their smooth arrangement and their fresh coloring. I lift the
thing. It is light, very dry and gives a hard sound, like an old
shoe tanned by the summer sun in the fields. There is no smell.
The dryness has vanquished the stench, which, in any case, was
never offensive during that time of frost. On the other hand, the
back, which touched the sand, is a loathsome wreck, partly deprived
of its feathers. The quills of the tail are bare barreled; a few
whitened bones show, deprived of their muscles. The skin has
turned into a dark leather, pierced with round holes like those of
a sieve. It is all hideously ugly, but most instructive.
The wretched owl, with his shattered backbone, teaches us, first of
all, that a temperature twelve degrees of frost does not endanger
the existence of the bluebottle's germs. The worms were born
without accident, despite the rude blast; they feasted copiously on
extract of meat; then, growing big and fat, they descended into the
earth by piercing round holes in the bird's skin. Their pupae must
now be in the sand of the pan.
They are, in point of fact, and in such numbers that I have to
resort to sifting in order to collect them. If I used the forceps,
I should never have done sorting so great a quantity. The sand
passes through the meshes of the sieve, the pupae remain above. To
count them would wear out my patience. I measure them by the
bushel, that is to say, with a thimble of which I know the holding
capacity in pupae. The result of my calculation is not far short
of nine hundred.
Does this family proceed from one mother? I am quite ready to
admit it, so unlikely is it that the bluebottle, who is so rare
inside our houses during the severe cold of winter, should be
frequent enough outside to form into groups and to do business in
common while an icy blast is raging. A belated specimen, the
plaything of the north wind, and one alone must have deposited the
burden of her ovaries on the owl's eyes. This laying of nine
hundred eggs, an incomplete laying perhaps, bears witness to the
mighty part played by the fly as a liquidator of corpses.
Before throwing away the screech owl treated by the worms, let us
overcome our repugnance and give a glance inside the bird. We see
a tortuous cavity, fenced in by nameless ruins. Muscles and bowels
have disappeared, converted into broth and gradually consumed by
the teeming throng. In every part, what was wet has become dry,
what was solid muddy. In vain my forceps ransacks every nook and
corner: it does not hit upon a single pupa. All the worms have
emigrated, all, without exception. From first to last, they have
forsaken the refuge of the corpse, so soft to their delicate skins;
they have left the velvet for the hard ground. Is dryness
necessary to them at this stage? They had it in the carcass, which
was thoroughly drained. Would they protect themselves against the
cold and rain? No shelter could suit them better than the thick
quilt of the feathers, which has remained wholly undamaged on the
belly, the breast and every part that was not in touch with the
ground. It looks as though they had fled from comfort to seek a
less kindly dwelling place. When the hour of transformation came,
all left the owl, that most excellent lodging; all dived into the
sand.
The exodus from the mortuary tabernacle was made through the round
holes wherewith the skin is pierced. Those holes are the worms'
work: of that there is no doubt; and yet we have lately seen the
mothers refuse as a bed for their eggs any part whereat the flesh
is protected by a skin of some thickness. The reason is the
failure of the pepsin to act on epidermic substances. In the
absence of liquefaction at such points, the nourishing gruel is
unprocurable. On the other hand, the tiny worms are not able--or
at least do not know how--to dig through the integument with their
pair of guttural harpoons, to rend it and reach the liquefiable
flesh. The newborn lack strength and, above all, purpose. But, as
the time comes for descending into the earth, the worms, now
powerful and suddenly versed in the necessary art, well know how to
eat away patiently and clear themselves a passage. With the hooks
of their spikes they dig, scratch and tear. Instinct has flashes
of inspiration. What the animal did not know how to do at the
start it learns without apprenticeship when the time comes to
practice this or that industry. The maggot ripe for burial
perforates a membranous obstacle which the grub intent upon its
broth would not even have attempted to attack with either its
pepsin or its grapnels.
Why does the worm quit the carcass, that capital shelter? Why does
it go and take up its abode in the ground? As the leading
disinfector of dead things, it works at the most important matter,
the suppression of the infection; but it leaves a plentiful
residuum, which does not yield to the reagents of its analytical
chemistry. These remains have to disappear in their turn. After
the fly, anatomists come hastening, who take up the dry relic,
nibble skin, tendons and ligaments and scrape the bones clean.
The greatest expert in this work is the Dermestes beetle, an
enthusiastic gnawer of animal remains. Sooner or later, he will
come to the joint already exploited by the fly. Now what would
happen if the pupae were there? The answer is obvious. The
Dermestes, who loves hard food, would dig his teeth into the horny
little kegs and demolish them at a bite. Even though he did not
touch the contents, a live thing which he probably dislikes, he
would at least test the flavor of that lifeless substance, the
container. The future Fly would be lost, because her casing would
be pierced. Even so, in the storerooms of our silk mills, a
certain Dermestes (Dermestes vulpinus, FABR.) digs into the cocoons
to attack the horny covering of the chrysalis.
The maggot foresees the danger and makes itself scarce before the
other arrives. In what sort of memory does it house so much
wisdom, indigent, headless creature that it is, for it is only by
extension that we can give the name of head to the animal's pointed
fore part? How did it learn that, to safeguard the pupa, it must
desert the carcass and that, to safeguard the fly, it must not bury
itself too far down?
To emerge from underground after the perfect insect is hatched, the
bluebottle's device consists in disjointing her head into two
movable halves, which, each distended with its great red eye, by
turns separate and reunite. In the intervening space, a large,
glassy hernia rises and disappears, disappears and rises. When the
two move asunder, with one eye forced back to the right, the other
to the left, it is as though the insect were splitting its brain
pan in order to expel the contents. Then the hernia rises, blunt
at the end and swollen into a great knob. Next, the forehead
closes and the hernia retreats, leaving visible only a kind of
shapeless muzzle. In short, a frontal pouch, with deep pulsations
momentarily renewed, becomes the instrument of deliverance, the
pestle wherewith the newly hatched bluebottle bruises the sand and
causes it to crumble. Gradually the legs push the rubbish back and
the insect advances so much toward the surface.
A hard task, this exhumation by dint of the blows of a cleft and
palpitating head. Moreover, the exhausting effort has to be made
at the moment of greatest weakness, when the insect leaves that
protecting casket, its pupa. It emerges from it pale, flabby and
unsightly, sorrily clad in the wings which, folded lengthwise and
made shorter by their scalloped edge, only just cover the top of
the back. Wildly bristling with hairs and colored ashen-gray, it
is a piteous sight. The large set of wings, suitable for flight,
will spread later. For the moment, it would only be in the way
amid the obstacles to be passed through. Later also will come the
faultless dress wherein the iridescent indigo-blue stands out
against the severity of the black.
The frontal hernia that crumbles the sand with its impact has a
tendency to make play for some time after the emergence from the
ground. Take hold with the forceps of one of the hind legs of a
newly released fly. Forthwith, the implement of the head begins to
work, swelling and subsiding as energetically as a moment ago, when
it had to make a hole in the sand. The insect, hampered in its
movements as when it was underground, struggles as best it can
against the only obstacle that it knows. With its heaving knob, it
pounds the air even as but now it pounded the earthy barrier. In
all unpleasant circumstances, its one resource is to cleave its
head and produce its cranial hernia, which moves out and in, in and
out. For nearly two hours, interspersed with halts due to fatigue,
the little machine keeps throbbing in my forceps.
In the meantime, however, the desperate one is hardening her skin;
she spreads wide the sail of her wings and dons her deep mourning
of black and darkest blue. Then her eyes, warped sideways, come
together and resume their normal position. The cleft forehead
closes; the delivering blister goes in, never to show itself again.
But there is one precaution to be taken first. With its front
tarsi, the insect carefully brushes the bump about to disappear
from view, lest grit should lodge in the cranium when the two
halves of the head are joined for good.
The maggot is aware of the trials that await it when, as a fly, it
will have to come up from under ground; it knows beforehand how
difficult the ascent will be with the feeble instrument at its
disposal, so difficult, in fact, as to become fatal should the
journey be at all prolonged. It foresees the dangers ahead of it
and averts them as well as it can. Gifted with two iron shod
sticks in its throat, it can easily descend to such depths as it
pleases. The need for greater quiet and a less trying temperature
calls for the deepest possible home: the lower down it is, the
better for the welfare of the worm and the pupa, on condition that
descent be practicable. It is, perfectly; and yet, though free to
obey its inspiration, the grub refrains. I rear it in a deep pan,
full of fine, dry sand, easy to excavate. The interment never goes
very far. About a hand's breadth is all that the most progressive
digger ventures upon. Most of the interred remain nearer still to
the surface. Here, under a thin layer of sand, the grub's skin
hardens and becomes a coffin, a casket, wherein the transformation
sleep is slept. A few weeks later, the buried one awakes,
transfigured but weak, having naught wherewith to unearth herself
but the throbbing hernia of her open forehead.
What the maggot denies itself it is open to me to realize, should I
care to know the depth whence the fly is able to mount. I place
fifteen bluebottle pupae, obtained in winter, at the bottom of a
wide tube closed at one end. Above the pupae is a perpendicular
column of fine, dry sand, the height of which varies in different
tubes. April comes and the hatching begins.
A tube with six centimeters of sand, the shallowest of the columns
under experiment, yields the best result. Of the fifteen subjects
interred in the pupa stage, fourteen easily reach the surface when
they become flies. Only one of them perishes, one who has not even
attempted the ascent. With twelve centimeters of sand, four
emerge. With twenty centimeters, two, no more. The other flies,
jaded with their exertions, have died at a higher or lower stage of
the road. Lastly, with yet another tube wherein the column of sand
measured sixty centimeters, I obtained the liberation of only a
single fly. The plucky creature must have had a hard struggle to
mount from so great a depth, for the other fourteen did not even
manage to burst the lid of their caskets.
I presume that the looseness of the sand and the consequent
pressure in every direction, similar to that exercised by fluids,
have a certain bearing on the difficulties of the exhumation. Two
more tubes are prepared, but this time supplied with fresh mould,
lightly heaped up, which has not the incoherence of sand, with the
attendant drawback of pressure. Six centimeters of mould give me
eight flies for fifteen pupae buried; twenty centimeters give me
only one. There is less success than with the sandy column. My
device has diminished the pressure, but, at the same time,
increased the passive resistance. The sand falls of itself under
the impact of the frontal rammer; the unyielding mould demands the
cutting of a gallery. In fact, I perceive, on the road followed, a
shaft which continues indefinitely such as it is. The fly has
bored it with the temporary blister that throbs between her eyes.
In every medium, therefore, whether sand, mould or any earthy
combination, great are the sufferings that attend the exhumation of
the fly. And so the maggot shuns the depths which a desire for
additional security might seem to recommend. The worm has its own
prudence: foreseeing the dangers ahead, it refrains from making
great descents that might promote the welfare of the moment. It
neglects the present for the sake of the future.
CHAPTER XVI A PARASITE OF THE MAGGOT
The dangers of the exhumation are not the only ones; the Bluebottle
must be acquainted with others. Life, when all is said, is a
knacker's yard wherein the devourer of today becomes the devoured
of tomorrow; and the robber of the dead cannot fail to be robbed of
her own life when the time comes. I know that she has one
exterminator in the person of the tiny Saprinus beetle, a fisher of
fat sausages on the edge of the pools formed by liquescent corpses.
Here swarm in common the grubs of the greenbottle, the flesh fly
and the bluebottle. The Saprinus draws them to him from the bank
and gobbles them indiscriminately. They represent to him morsels
of equal value.
This banquet can be observed only in the open country, under the
rays of a hot sun. Saprini and greenbottles never enter our
houses; the flesh fly visits us but discreetly, does not feel at
home with us; the only one who comes fussing along is the
bluebottle, who thus escapes the tribute due to the consumer of
plump sausages. But, in the fields, where she readily lays her
eggs upon any carcass that she finds, she, as well as the others,
sees her vermin swept away by the gluttonous Saprinus.
In addition, graver disasters decimate her family, if, as I do not
doubt, we can apply to the bluebottle what I have seen happen in
the case of her rival, the flesh fly. So far, I have had no
opportunity of actually perceiving with the first what I have to
tell of the second; still, I do not hesitate to repeat about the
one what observation has taught me about the other, for the larval
analogies between the two flies are very close.
Here are the facts. I have gathered a number of pupae of the flesh
fly in one of my vermin jars. Wishing to examine the pupa's hinder
end, which is hollowed into a cup and scalloped into a coronet, I
stave in one of the little barrels and force open the last segments
with the point of my pocketknife. The horny keg does not contain
what I expected to find: it is full of tiny grubs packed one atop
the other with the same economy of space as anchovies in a bottle.
Save for the skin, which has hardened into a brown shell, the
substance of the maggot has disappeared, changed into a restless
swarm.
There are thirty-five occupants. I replace them in their casket.
The rest of my harvest, wherein, no doubt, are other pupae
similarly stocked, is arranged in tubes that will easily show me
what happens. The thing to discover is what genus of parasites the
grubs enclosed belong to. But it is not difficult, without waiting
for the hatching of the adults, to recognize their nature merely by
their mode of life. They form part of the family of Chalcididae,
who are microscopic ravagers of living entrails.
Not long ago, in winter, I took from the chrysalis of a great
peacock moth four hundred and forty-nine parasites belonging to the
same group. The whole substance of the future moth had
disappeared, all but the nymphal wrapper, which was intact and
formed a handsome Russia-leather wallet. The worm grubs were here
heaped up and squeezed together to the point of sticking to one
another. The hair pencil extracts them in bundles and cannot
separate them without some difficulty. The holding capacity is
strained to the utmost; the substance of the vanished Moth would
not fill it better. That which died has been replaced by a living
mass of equal dimensions, but subdivided. The price of this
colony's existence is the conversion of the chrysalis into a sort
of milk food of doubtful constitution. The enormous udder has been
drained outright.
You shudder when you think of that budding flesh nibbled bit by bit
by four or five hundred gormandizers; the horrified imagination
refuses to picture the anguish suffered by the tortured wretch.
But is there really any pain? We have leave to doubt it. Pain is
a patent of nobility; it is more pronounced in proportion as the
sufferer belongs to a higher order. In the lower ranks of animal
life, it must be greatly reduced, perhaps even nil, especially when
life, in the throes of evolution, has not yet acquired a stable
equilibrium. The white of an egg is living matter, but endures the
prick of a needle without a quiver. Would it not be the same with
the chrysalis of the great peacock, dissected cell by cell by
hundreds of infinitesimal anatomists? Would it not be the same
with the pupa of the flesh fly? These are organisms put back into
the crucible, reverting to the egg state for a second birth. There
is reason to believe, therefore, that their destruction crumb by
crumb is merciful.
Towards the end of August, the parasite of the flesh fly's grubs
makes her appearance out of doors in the adult form. She is a
Chalcidid, as I expected. She issues from the barrel through one
or two little round holes which the prisoners have pierced with a
patient tooth. I count some thirty to each pupa. There would not
be enough room in the abode if the family were larger.
The imp is a slim and elegant creature, but oh, how small! She
measures hardly two millimeters. Her garb is bronzed black, with
pale legs and a heart shaped, pointed, slightly pedunculate
abdomen, with never a trace of a probe for inoculating the eggs.
The head is transversal, the width exceeding the length.
The male is only half the size of the female; he is also very much
less numerous. Perhaps pairing is here, as we see elsewhere, a
secondary matter from which it is possible to abstain, in part,
without injuring the prospects of the race. Nevertheless, in the
tube wherein I have housed the swarm, the few males lost among the
crowd ardently woo the passing fair. There is much to be done
outside, as long as the flesh fly's season lasts; things are
urgent; and each pigmy hurries as fast as she can to take up her
part as an exterminator.
How is the parasite's inroad into the flesh fly's pupae effected?
Truth is always veiled in a certain mystery. The good fortune that
secured me the ravaged pupa taught me nothing concerning the
tactics of the ravager. I have never seen the Chalcidid explore
the contents of my appliances; my attention was engaged elsewhere
and nothing is so difficult to see as a thing not yet suspected.
But, though direct observation be lacking, logic will tell us
approximately what we want to know.
It is evident, to begin with, that the invasion cannot have been
made through the sturdy amour of the pupae. This is too hard to be
penetrated by the means at the pigmy's disposal. Naught but the
delicate skin of the maggots lends itself to the introduction of
the germs. An egg laying mother, therefore, appears, inspects the
surface of the pool of sanies swarming with grubs, selects the one
that suits her and perches on it; then, with the tip of her pointed
abdomen, whence emerges, for an instant, a short probe kept hidden
until then, she operates on the patient, perforating his paunch
with a dexterous wound into which the germs are inserted.
Probably, a number of pricks are administered, as the presence of
thirty parasites seems to demand.
Anyway, the maggot's skin is pierced at either one point or many;
and this happens while the grub is swimming in the pools formed by
the putrid flesh. Having said this, we are faced with a question
of serious interest. To set it forth necessitates a digression
which seems to have nothing to do with the subject in hand and is
nevertheless connected with it in the closest fashion. Without
certain preliminaries, the remainder would be unintelligible. So
now for the preliminaries.
I was in those days busy with the poison of the Languedocian
scorpion and its action upon insects. To direct the sting toward
this or the other part of the victim and moreover to regulate its
emission would be absolutely impossible and also very dangerous, as
long as the scorpions were allowed to act as they pleased. I
wished to be able myself to choose the part to be wounded; I
likewise wished to vary the dose of poison at will. How to set
about it? The scorpion has no jarlike receptacle in which the
venom is accumulated and stored, like that possessed, for instance,
by the wasp and the bee. The last segment of the tail, gourd
shaped and surmounted by the sting, contains only a powerful mass
of muscles along which lie the delicate vessels that secrete the
poison.
In default of a poison jar which I would have placed on one side
and drawn upon at my convenience, I detach the last segment,
forming the base of the sting. I obtain it from a dead and already
withered scorpion. A watch glass serves as a basin. Here, I tear
and crush the piece in a few drops of water and leave it to steep
for four-and-twenty hours. The result is the liquid which I
propose to use for the inoculation. If any poison remained in my
animal's caudal gourd, there must be at least some traces of it in
the infusion in the watch glass.
My hypodermic syringe is of the simplest. It consists of a little
glass tube, tapering sharply at one end. By drawing in my breath,
I fill it with the liquid to be tested; I expel the contents by
blowing. Its point is almost as fine as a hair and enables me to
regulate the dose to the degree which I want. A cubic millimeter
is the usual charge. The injection has to be made at parts that
are generally covered with horn. So as not to break the point of
my fragile instrument, I prepare the way with a needle, with which
I prick the victim at the spot required. I insert the tip of the
loaded injector in the hole thus made and I blow. The thing is
done in a moment, very neatly and in an orthodox fashion, favorable
to delicate experiments. I am delighted with my modest apparatus.
I am equally delighted with the results. The scorpion himself,
when wounding with his sting, in which the poison is not diluted as
mine is in the watch glass, would not produce effects like those of
my pricks. Here is something more brutal, producing more
convulsion in the sufferer. The virus of my contriving excels the
scorpion's.
The test is several times repeated, always with the same mixture,
which, drying up by spontaneous evaporation, then made to serve
again by the addition of a few drops of water, once more drained
and once more moistened, does duty for an indefinite length of
time. Instead of abating, the virulence increases. Moreover, the
corpses of the insects operated upon undergo a curious change,
unknown in my earlier observations. Then the suspicion comes to me
that the actual poison of the scorpion does not enter into the
matter at all. What I obtain with the end joint of the tail, with
the gland at the base of the sting, I ought to obtain with any
other part of the animal.
I crush in a few drops of water a joint of the tail taken from the
front portion, far from the poison glands. After soaking it for
twenty-four hours, I obtain a liquid whose effects are absolutely
the same as those before, when I used the joint that bears the
sting. I try again with the scorpion's claws, the contents of
which consist solely of muscle. The results are just the same.
The whole of the animal's body, therefore, no matter which fragment
be submitted to the steeping process, yields the virus that so
greatly pricks my curiosity.
Every part of the Spanish fly [Cantharis or blistering beetle],
inside and out, is saturated with the blistering element; but there
is nothing like this in the scorpion, who localizes his venom in
his caudal gland and has none of it elsewhere. The cause of the
effects which I observe is therefore connected with general
properties which I ought to find in any insect, even the most
harmless.
I consult Oryctes nasicornis, the peaceable rhinoceros beetle, on
this subject. To get at the exact nature of the materials, instead
of pulverizing the whole insect in a mortar, I use merely the
muscular tissue obtained by scraping the inside of the dried
Oryctes' corselet. Or else I extract the dry contents of the hind
legs. I do the same with the desiccated corpses of the cockchafer,
the Capricorn, or Cerambyx beetle, and the Cetonia, or rosechafer.
Each of my gleanings, with a little water added, is left to soften
for a couple of days in a watch glass and yields to the liquid
whatever can be extracted from it by crushing and dissolving.
This time, we take a great step forward. All my preparations,
without distinction, are horribly virulent. Let the reader judge.
I select as my first patient the sacred beetle, Scarabaeus sacer,
who thanks to his size and sturdiness, lends himself admirably to
an experiment of this kind. I operate upon a dozen, in the
corselet, on the breast, on the belly and, by preference, on one of
the hind legs, far removed from the impressionable nervous centers.
No matter what part my injector attacks, the effect produced is the
same, or nearly. The insect falls as though struck by lightning.
It lies on its back and wriggles its legs, especially the hind
legs. If I set it on its feet again, I behold a sort of St.
Vitus' dance. Scarabaeus lowers his head, arches his back, draws
himself up on his twitching legs. He marks time with his feet on
the ground, moves forward a little, moves as much backward, leans
to the right, leans to the left, in wild disorder, incapable of
keeping his balance or making progress. And this happens with
sudden jerks and jolts, with a vigor no whit inferior to that of
the animal in perfect health. It is a displacement of all the
works, a storm that uproots the mutual relations of the muscles.
Seldom have I witnessed such sufferings, in my career as a cross-
examiner of animals and, therefore, as a torturer. I should feel a
scruple, did I not foresee that the grain of sand shifted today may
one day help us by taking its place in the edifice of knowledge.
Life is everywhere the same, in the Dung beetle's body as in man's.
To consult it in the insect means consulting it in ourselves, means
moving towards vistas which we cannot afford to neglect. That hope
justifies my cruel studies, which, though apparently so puerile,
are in reality worthy of serious consideration.
Of my dozen sufferers, some rapidly succumb, others linger for a
few hours. They are all dead by tomorrow. I leave the corpses on
the table, exposed to the air. Instead of drying and stiffening,
like the asphyxiated insects intended for our collections, my
patients, on the contrary, turn soft and slacken in the joints,
notwithstanding the dryness of the surrounding air; they become
disjointed and separate into loose pieces, which are easily
removed.
The results are the same with the Capricorn, the cockchafer, the
Procrustes [a large ground beetle], the Carabus [the true ground
beetle, including the gold beetle]. In all of them there is a
sudden break-up, followed by speedy death, a slackening of the
joints and swift putrefaction. In a non-horny victim, the quick
chemical changes of the tissues are even more striking. A Cetonia
grub, which resists the scorpion's sting, even though repeatedly
administered, dies in a very short time if I inject a tiny drop of
my terrible fluid into any part of its body. Moreover, it turns
very brown and, in a couple of days, becomes a mass of black
putrescence.
The great peacock, that large moth who recks little of the
scorpion's poison, is no more able to resist my inoculations than
the sacred beetle and the others. I prick two in the belly, a male
and a female. At first, they seem to bear the operation without
distress. They grip the trellis work of the cage and hang without
moving, as though indifferent. But soon the disease has them in
its grip. What we see is not the tumultuous ending of the sacred
beetle; it is the calm advent of death. With wings slackly
quivering, softly they die and drop from the wires. Next day, both
corpses are remarkably lax; the segments of the abdomen separate
and gape at the least touch. Remove the hairs and you shall see
that the skin, which was white, has turned brown and is changing to
black. Corruption is quickly doing its work.
This would be a good opportunity to speak of bacteria and cultures.
I shall do nothing of the sort. On the hazy borderland of the
visible and the invisible, the microscope inspires me with
suspicion. It so easily replaces the eye of reality by the eye of
imagination; it is so ready to oblige the theorists with just what
they want to see. Besides, supposing the microbe to be found, if
that were possible, the question would be changed, not solved. For
the problem of the collapse of the structure through the fact of a
prick there would be substituted another no less obscure: how does
the said microbe bring about that collapse? In what way does it go
to work? Where lies its power?
Then what explanation shall I give of the facts which I have just
set forth? Why, none, absolutely none, seeing that I do not know
of any. As I am unable to do better, I will confine myself to a
pair of comparisons or images, which may serve as a brief resting
place for the mind on the dark billows of the unknown.
All of us, as children, have amused ourselves with the game of
"card friars." A number of cards, as many as possible, are bent
lengthwise into a semi-cylinder. They are placed on a table, one
behind the other, in a winding row, the spaces in which are
suitably disposed. The performance pleases the eye by its curved
lines and its regular arrangement. It possesses order, which is a
condition of all animated matter. You give a little tap to the
first card. It falls and overturns the second, which, in the same
way, topsy-turvies the third; and so on, right to the end of the
row. In less than no time, the capsizing wave spreads and the
handsome edifice is shattered. Order is succeeded by disorder, I
might almost say, by death. What was needed thus to upset the
procession of friars? A very, very slight first push, out of all
proportion to the toppled mass.
Again, take a glass balloon containing a solution of alum
supersaturated by heat. It is closed, during the process of
boiling, with a cork and is then allowed to cool. The contents
remain fluid and limpid for an indefinite period. Mobility is here
represented by a faint semblance of life. Remove the cork and drop
in a solid particle of alum, however infinitesimal. Suddenly, the
liquid thickens into a solid lump and gives off heat. What has
happened? This: crystallization has set in at the first contact of
the particle of alum, the center of attraction; next, it has spread
bit by bit, each solidified particle producing the solidification
of those around. The impulse comes from an atom; the mass impelled
is boundless. The very small has revolutionized the immense.
Of course, in the comparison between these two instances and the
effects of my injections, the reader must see no more than a figure
of speech, which, without explaining anything, tries to throw a
glimmer of light upon it. The long procession of card friars is
knocked down by the mere touch of the little finger to the first;
the voluminous solution of alum suddenly turns solid under the
influence of an invisible particle. In the same way, the victims
of my operations succumb, thrown into convulsions by a tiny drop of
insignificant size and harmless appearance.
Then what is there in that terrible liquid? First of all, there is
water, inactive in itself and simply a vehicle of the active agent.
If a proof were needed of its innocuousness, here is one: I inject
into the thigh of any one of the sacred beetle's six legs a drop of
pure water larger than that of the fatal inoculations. As soon as
he is released, he makes off and trots about as nimbly as usual.
He is quite firm on his legs. When put back to his pellet, he
rolls it with the same zeal as before the experiment. My injection
of water makes no difference to him.
What else is there in the mixture in my watch glasses? There is
the disintegrated matter of the corpse, especially shreds of dried
muscles. Do these substances yield certain soluble elements to
water? Or are they simply reduced to a fine dust in the crushing?
I will not decide this question, nor is it really of importance.
The fact remains that the poison proceeds from those substances and
from them alone. Animal matter, therefore, which has ceased to
live is an agent of destruction within the organism. The dead cell
kills the living cell; in the delicate statics of life, it is the
grain of sand which, refusing its support, entails the collapse of
the whole edifice.
In this connection, we may recall those dreadful dissecting room
accidents. Through awkwardness, a student of anatomy pricks
himself with his scalpel in the course of his work; or else, by
inadvertence, he has an insignificant scratch on his hand. A cut
which one would hardly notice, produced by the point of a pocket
knife, a scratch of no account, from a thorn or otherwise, now
becomes a mortal wound, if powerful antiseptics do not speedily
remedy the ill. The scalpel is soiled by its contact with the
flesh of the corpse; so are the hands. That is quite enough. The
virus of corruption is introduced; and, if not treated in time, the
wound proves fatal. The dead has killed the living. This also
reminds us of the so-called carbuncle flies, the lancet of whose
mouth parts, contaminated with the sanies of corpses, produces such
terrible accidents.
My dealings as against insects are, when all is said, nothing but
dissecting room wounds and carbuncle flies' stings. In addition to
the gangrene that soon impairs and blackens the tissues, I obtain
convulsions similar to those produced by the scorpion's sting. In
its convulsive effects, the venomous fluid emitted by the sting
bears a close resemblance to the muscular infusions with which I
fill my injector. We are entitled, therefore, to ask ourselves if
poisons, generally speaking, are not themselves a produce of
demolition, a casting of the organism perpetually renewed, waste
matter, in short, which, instead of being gradually expelled, is
stored for purposes of attack and defense. The animal, in that
case, would arm itself with its own refuse in the same way as it
sometimes builds itself a home with its intestinal recrement.
Nothing is wasted; life's detritus is used for self defense.
All things considered, my preparations are meat extracts. If I
replace the flesh of the insect by that of another animal, the ox,
for instance, shall I obtain the same results? Logic says yes; and
logic is right. I dilute with a few drops of water a little
Liebig's extract, that precious standby of the kitchen. I operate
with this fluid on six Cetoniae or rosechafers, four in the grub
stage, two in the adult stage. At first, the patients move about
as usual. Next day, the two Cetoniae are dead. The larvae resist
longer and do not die until the second day. All show the same
relaxed muscles, the same blackened flesh, signs of putrefaction.
It is probable, therefore, that, if injected into our own veins,
the same fluid would likewise prove fatal. What is excellent in
the digestive tubes would be appalling in the arteries. What is
food in one case is poison in the other.
A Liebig's extract of a different kind, the broth in which the
liquefier puddles, is of a virulence equal, if not superior, to
that of my products. All those operated upon, Capricorns, sacred
beetles, ground beetles, die in convulsions. This brings us back,
after a long way round, to our starting point, the maggot of the
flesh fly. Can the worm, constantly floundering in the sanies of a
carcass, be itself in danger of inoculation by that whereon it
grows fat? I dare not rely upon experiments conducted by myself:
my clumsy implements and my shaky hand make me fear that, with
subjects so small and delicate, I might inflict deep wounds which
of themselves would bring about death.
Fortunately, I have a collaborator of incomparable skill in the
parasitic Chalcidid. Let us apply to her. To introduce her germs,
she has perforated the maggot's paunch, has even done so several
times over. The holes are extremely small, but the poison all
around is excessively subtle and has thus been able, in certain
cases, to penetrate. Now what has happened? The pupae, all from
the same apparatus, are numerous. They can be divided into three
not very unequal classes, according to the results supplied. Some
give me the adult flesh fly, others the parasite. The rest, nearly
a third, give me nothing, neither this year nor next.
In the first two cases, things have taken their normal course: the
grub has developed into a fly, or else the parasite has devoured
the grub. In the third case, an accident has occurred. I open the
barren pupae. They are coated inside with a dark glaze, the
remains of the dead maggot converted into black rottenness. The
grub, therefore, has undergone inoculation by the virus through the
fine openings effected by the Chalcidid. The skin has had time to
harden into a shell; but it was too late, the tissues being already
infected.
There you see it: in its broth of putrefaction, the worm is exposed
to grave dangers. Now there is a need for maggots in this world,
for maggots many and voracious, to purge the soil as quickly as
possible of death's impurities. Linnaeus tells us that 'Tres
muscae consumunt cadaver equi aeque cito ac leo." [Three flies
consume the carcass of a horse as quickly as a lion could do it.]
There is no exaggeration about the statement. Yes, of a certainty,
the offspring of the flesh fly and the bluebottle are expeditious
workers. They swarm in a heap, always seeking, always snuffling
with their pointed mouths. In those tumultuous crowds, mutual
scratches would be inevitable if the worms, like the other flesh
eaters, possessed mandibles, jaws, clippers adapted for cutting,
tearing and chopping; and those scratches, poisoned by the dreadful
gruel lapping them, would all be fatal.
How are the worms protected in their horrible work yard? They do
not eat: they drink their fill; by means of a pepsin which they
disgorge, they first turn their foodstuffs into soup; they practice
a strange and exceptional art of feeding, wherein those dangerous
carving implements, the scalpels with their dissecting room perils,
are superfluous. Here ends, for the present, the little that I
know or suspect of the maggot, the sanitary inspector in the
service of the public health.
CHAPTER XVII RECOLLECTIONS OF CHILDHOOD
Almost as much as insects and birds--the former so dear to the
child, who loves to rear his cockchafers and rose beetles on a bed
of hawthorn in a box pierced with holes; the latter an irresistible
temptation, with their nests and their eggs and their little ones
opening tiny yellow beaks--the mushroom early won my heart with its
varied shapes and colors. I can still see myself as an innocent
small boy sporting my first braces and beginning to know my way
through the cabalistic mazes of my reading book, I see myself in
ecstasy before the first bird's nest found and the first mushroom
gathered. Let us relate these grave events. Old age loves to
meditate the past.
O happy days when curiosity awakens and frees us from the limbo of
unconsciousness, your distant memory makes me live my best years
over again. Disturbed at its siesta by some wayfarer, the
partridge's young brood hastily disperses. Each pretty little ball
of down scurries off and disappears in the brushwood; but, when
quiet is restored, at the first summoning note they all return
under the mother's wing. Even so, recalled by memory, do my
recollections of childhood return, those other fledglings which
have lost so many of their feathers on the brambles of life. Some,
which have hardly come out of the bushes, have aching heads and
tottering steps; some are missing, stifled in some dark corner of
the thicket; some remain in their full freshness. Now of those
which have escaped the clutches of time the liveliest are the
first-born. For them the soft wax of childish memory has been
converted into enduring bronze.
On that day, wealthy and leisured, with an apple for my lunch and
all my time to myself, I decided to visit the brow of the
neighboring hill, hitherto looked upon as the boundary of the
world. Right at the top is a row of trees which, turning their
backs to the wind, bend and toss about as though to uproot
themselves and take to flight. How often, from the little window
in my home, have I not seen them bowing their heads in stormy
weather; how often have I not watched them writhing like madmen
amid the snow dust which the north wind's broom raises and smoothes
along the hillside! 'What are they doing up there, those desolate
trees? I am interested in their supple backs, today still and
upright against the blue of the sky, tomorrow shaken when the
clouds pass overhead. I am gladdened by their calmness; I am
distressed by their terrified gestures. They are my friends. I
have them before my eyes at every hour of the day. In the morning,
the sun rises behind their transparent screen and ascends in its
glory. Where does it come from? I am going to climb up there and
perhaps I shall find out.
I mount the slope. It is a lean grass sward close-cropped by the
sheep. It has no bushes, fertile in rents and tears, for which I
should have to answer on returning home, nor any rocks, the scaling
of which involves like dangers; nothing but large, flat stones,
scattered here and there. I. have only to go straight on, over
smooth ground. But the sward is as steep as a sloping roof. It is
long, ever so long; and my legs are very short. From time to time,
I look up. My friends, the trees on the hilltop, seem to be no
nearer. Cheerily, sonny! Scramble away!
What is this at my feet? A lovely bird has flown from its hiding
place under the eaves of a big stone. Bless us, here's a nest made
of hair and fine straw! It's the first I have ever found, the first
of the joys which the birds are to bring me. And in this nest are
six eggs, laid prettily side by side; and those eggs are a
magnificent blue, as though steeped in a dye of celestial azure.
Overpowered with happiness, I lie down on the grass and stare.
Meanwhile, the mother, with a little clap of her gullet--'Tack!
Tack !'--flies anxiously from stone to stone, not far from the
intruder. My age knows no pity, is still too barbarous to
understand maternal anguish. A plan is running in my head, a plan
worthy of a little beast of prey. I will come back in a fortnight
and collect the nestlings before they can fly away. In the
meantime, I will just take one of those pretty blue eggs, only one,
as a trophy. Lest it should be crushed, I place the fragile thing
on a little moss in the scoop of my hand. Let him cast a stone at
me that has not, in his childhood, known the rapture of finding his
first nest.
My delicate burden, which would be ruined by a false step, makes me
give up the remainder of the climb. Some other day I shall see the
trees on the hilltop over which the sun rises. I go down the slope
again. At the bottom, I meet the parish priest's curate reading
his breviary as he takes his walk. He sees me coming solemnly
along, like a relic bearer; he catches sight of my hand hiding
something behind my back: 'What have you there, my boy? ' he asks.
All abashed, I open my hand and show my blue egg on its bed of
moss.
'Ah!' says his reverence. 'A Saxicola's egg! Where did you get it?
'
'Up there, father, under a stone.'
Question follows question; and my peccadillo stands confessed. By
chance I found a nest which I was not looking for. There were six
eggs in it. I took one of them--here it is--and I am waiting for
the rest to hatch. I shall go back for the others when the young
birds have their quill feathers.
'You mustn't do that, my little friend,' replies the priest. 'You
mustn't rob the mother of her brood; you must respect the innocent
little ones; you must let God's birds grow up and fly from the
nest. They are the joy of the fields and they clear the earth of
its vermin. Be a good boy, now, and don't touch the nest.'
I promise and the curate continues his walk. I come home with two
good seeds cast on the fallows of my childish brain. An
authoritative word has taught me that spoiling birds' nests is a
bad action. I did not quite understand how the bird comes to our
aid by destroying vermin, the scourge of the crops; but I felt, at
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