The Life of the Fly
J. Henri Fabre

Part 3 out of 5

its scabbard. When I go fishing for caddis worms, I put them in
tin boxes, containing no other moisture than that wherewith my
catches are soaked. I heap them up loosely, to avoid any grievous
tumult and to fill the space at my disposal as best I may. I take
no further precaution. This is enough to keep the caddis worms in
good condition during the two or three hours which I devote to
fishing and to walking home.

On my return, I find that a number of them have left their houses.
They are swarming naked among the empty scabbards and those still
occupied by their inhabitants. It is a pitiful sight to see these
evicted ones dragging their bare abdomens and their frail
respiratory threads over the bristling sticks. There is no great
harm done, however; and I empty the whole lot into the glass pond.

Not one resumes possession of an unoccupied sheath. Perhaps it
would take them too long to find one of the exact size. They think
it better to abandon the old clouts and to manufacture cases new
from top to bottom. The process is a rapid one. By the next day,
with the materials wherein the glass trough abounds--bundles of
twigs and tufts of watercress--all the denuded worms have made
themselves at least a temporary home in the form of a tube of

The lack of water, combined with the excitement of the crowding in
the boxes, has upset my captives greatly; and, scenting a grave
peril, they have made off hurriedly, doffing the cumbersome jacket,
which is difficult to carry. They have stripped themselves so as
to flee with greater ease. The alarm cannot have been due to me:
there are not many simpletons like myself who are interested in the
affairs of the pond; and the caddis worm has not been cautioned
against their tricks. The sudden desertion of the crib has
certainly some other reason than man's molestations.

I catch a glimpse of this reason, the real one. The glass pond was
originally occupied by a dozen Dytisci, or water beetles, whose
diving performances are so curious to watch. One day, meaning no
harm and for want of a better receptacle, I fling among them a
couple of handfuls of caddis worms. Blunderer that I am, what have
I done! The corsairs, hiding in the rugged corners of the rock
work, at once perceive the windfall. They rise to the surface with
great strokes of their oars; they hasten and fling themselves upon
the crowd of carpenters. Each pirate grabs a sheath by the middle
and strives to rip it open by tearing off shells and sticks. While
this ferocious enucleation continues with the object of reaching
the dainty morsel contained within, the caddis worm, close pressed,
appears at the mouth of the sheath, slips out and quickly decamps
under the eyes of the Dytiscus, who appears to notice nothing.

I have said before that the trade of killing can dispense with
intelligence. The brutal ripper of sheaths does not see the little
white sausage that slips between his legs, passes under his fangs
and madly flees. He continues to tear away the outer case and to
tug at the silken lining. When the breach is made, he is quite
crestfallen at not finding what he expected.

Poor fool! Your victim went out under your nose and you never saw
it. The worm has sunk to the bottom and taken refuge in the
mysteries of the rock work. If things were happening in the large
expanse of a pond, it is clear that, with their system of
expeditious removals, most of the lodgers would escape scot-free.
Fleeing to a distance and recovering from the sharp alarm, they
would build themselves a new scabbard and all would be over until
the next attack, which would be baffled afresh by the selfsame

In my narrow trough, things take a more tragic turn. When the
sheaths are done for, when the caddis worms that are too slow in
making off have been eaten up, the Water beetles return to the
rockery at the bottom. Here, sooner or later, there are lamentable
happenings. The naked fugitives are discovered and, succulent
morsels that they are, are forthwith torn to pieces and devoured.
Within twenty-four hours, not one of my band of caddis worms is
left alive. In order to continue my studies, I had to lodge the
water beetles elsewhere.

Under natural conditions, the caddis worm has its persecutors, the
most formidable of whom appears to be the Water beetle. When we
consider that, to thwart the brigand's attacks, it has invented the
idea of quitting its scabbard with all speed, its tactics are
certainly most appropriate; but, in that case, an exceptional
condition becomes obligatory, namely, the capacity for recommencing
the work. This most unusual gift of recommencing it possesses in a
high measure. I am ready to see its origin in the persecutions of
the Dytiscus and other pirates. Necessity is the mother of

Certain caddis worms, of the Sericostoma and Leptocerus species,
clothe themselves in grains of sand and do not leave the bed of the
stream. On a clear bottom, swept by the current, they walk about
from one bank of verdure to the other and do not think of coming to
the surface to float and sail in the sunlight. The collectors of
sticks and shells are more highly privileged. They can remain on
the level of the water indefinitely, with no other support than
their skiff, can rest in unsubmersible flotillas and can even shift
their place by working the rudder.

To what do they owe this privilege? Are we to look upon the bundle
of sticks as a sort of raft whose density is less than that of the
water? Can the shells, which are always empty and able to contain
a few bubbles of air in their spiral, be floats? Can the big
joists, which break in so ugly a fashion the none too great
regularity of the work, serve to buoy up the over-heavy raft? In
short, is the caddis worm versed in the laws of equilibrium and
does it choose its pieces, now lighter and now heavier as the case
may be, so as to constitute a whole that is capable of floating?
The following facts are a refutation of any such hydrostatic
calculations in the animal.

I remove a number of caddis worms from their sheaths and submit
these, as they are, to the test of water. Whether formed wholly of
fibrous remnants or of mixed materials, not one of them floats.
The scabbards made of shells go to the bottom with the swiftness of
a bit of gravel; the others sink gently. I experiment with the
separate materials one by one. No shell remains on the surface,
not even among the Planorbes, which a many-whorled spiral ought,
one would think, to keep afloat. The fibrous remnants must be
divided into two categories. The first, darkened by time and
soaked with moisture, sink to the bottom. These are the most
plentiful. The second, considerably fewer in number, of more
recent date and less saturated with water, float very well. The
general result is immersion, as in the case of the intact
scabbards. I may add that the animal, when removed from its tube,
is also unable to float.

Then how does the caddis worm manage to remain on the surface
without the support of the grasses, considering that itself and its
sheath are both heavier than water? Its secret is soon revealed.
I place a few high and dry on a sheet of blotting paper, which will
absorb the excess of liquid unfavorable to successful observation.
Outside its natural environment, the animal moves about violently
and restlessly. With its body half out of the scabbard, this time
composed entirely of fibrous matter, it clutches with its feet at
the supporting plane. Then, contracting itself, it draws the
scabbard towards it, half-raising it and sometimes even making it
assume a vertical position. Even so do the Bulimi move along,
lifting their shell as they complete each crawling step.

After a couple of minutes in the free air, I replace the caddis
worm in the water. This time, it floats, but like a cylinder with
too much weight below. The sheath remains vertical, with its
hinder orifice level with the water. Soon, an air bubble escapes
from the orifice. Deprived of this buoy, the skiff at once goes

The result is the same with the caddis worms in shell casings. At
first, they float, straight up on end, and then dip under and sink,
faster than the others, after sending out an air bubble or two
through the back window.

That is enough: the secret is out. When cased in wood or in
shells, the caddis worms, which are always heavier than water, are
able to keep on the surface by means of a temporary air balloon
which decreases the density of the whole structure.

This apparatus works in the simplest manner. Consider the rear of
the sheath. It is truncated, wide open and supplied with a
membranous partition, the work of the spinneret. A round hole
occupies the center of this screen. Beyond it lies the interior of
the scabbard, which is smoothly lined and wadded with satin,
however rough the exterior may be. Armed at the stern with two
hooks which bite into the silky lining, the animal is able to move
backwards and forwards at will inside the cylinder, to fix its
grapnels at whatever point it pleases and thus to keep a hold on
the cylinder while the six legs and the fore part are outside.

When at rest, the body remains indoors entirely and the grub
occupies the whole of the tube. But let it contract ever so little
towards the front, or, better still, let it stick out a part of its
body: a vacuum is formed behind this sort of piston, which may be
compared with that of a pump. Thanks to the rear window, a valve
without a plug, this vacuum at once fills, thus renewing the
aerated water around the gills, a soft fleece of hairs distributed
over the back and belly.

The piston stroke affects only the work of breathing; it does not
alter the density, makes hardly any change in that which is heavier
than water. To lighten the weight, the caddis worm must first rise
to the surface. With this object, it scales the grasses of one
support after the other; it clambers up, sticking to its purpose in
spite of the drawback of its faggot dragging through the tangle.
When it has reached the goal, it lifts the rear end a little above
the water and gives a stroke of the piston. The vacuum thus
obtained fills with air. That is enough: skiff and boatman are in
a position to float. The now useless support of the grasses is
abandoned. The time has come for evolutions on the surface, in the
glad sunlight.

The caddis worm possesses no great talent as a navigator. To turn
round, to tack about, to shift its place slightly by a backward
movement is all that it can do; and even that it does very
clumsily. The front part of the body, sticking out of the case,
acts as a rudder. Three or four times over, it rises abruptly,
bends, comes down again and strikes the water. These paddle
strokes, repeated at intervals, carry the unskilled oarsman to
fresh latitudes. It becomes a voyage on the right seas when the
crossing measures a hand's breadth.

However, tacking on the surface of the water affords the caddis
worm no pleasure. It prefers to twitter in one spot, to remain
stationary in flotillas. When the time comes to return to the
quiet of the mud bed at the bottom, the animal, having had enough
of the sun, draws itself wholly into its sheath again and, with a
piston stroke, expels the air from the back room. The normal
density is restored and it sinks slowly to the bottom.

We see, therefore, that the caddis worm has not to trouble about
hydrostatics when building its scabbard. In spite of the
incongruity of its work, in which the bulky and less dense portions
seem to balance the more solid, concentrated part, it is not called
upon to contrive an equipoise between the light and the heavy. It
has other artifices whereby to rise to the surface, to float and to
dive down again. The ascent is made by the ladder of the water
weeds. The average density of the sheath is of no importance, so
long as the burden to be dragged is not beyond the animal's
strength. Besides, the weight of the load is greatly reduced when
moved in the water.

The admission of a bubble of air into the back chamber, which the
animal ceases to occupy, allow it, without further to-do, to remain
for an indefinite period on the surface. To dive down again, the
caddis worm has only to retreat entirely into its sheath. The air
is driven out; and the canoe, resuming its mean density, a greater
specific density than that of water, goes under at once and
descends of its own accord.

There is, therefore, no choice of materials on the builder's part,
no nice calculation of equilibrium, save for one condition, that no
stony matter be admitted. That apart, everything serves, large and
small, joist and shell, seed and billet. Built up at haphazard,
all these things make an impregnable wall. One point alone is
essential: the weight of the whole must slightly exceed that of the
water displaced; if not, there could be no steadiness at the bottom
of the pond, without a perpetual anchorage struggling against the
pull of the water. In the same manner, quick submersion would be
impossible at times when the surface became dangerous and the
frightened creature wanted to leave it.

Nor does this important heavier-than-water question call for lucid
discernment, seeing that almost the whole of the sheath is
constructed at the bottom of the pond, whither all the materials
picked up at random, having descended once before, are likely to
descend again. In the sheaths, the parts capable of floating are
very rare. Without taking their specific levity into account,
simply so as not to remain idle, the caddis worm fixed them to its
bundle when sporting on the surface of the water.

We have our submarines, in which hydraulic ingenuity displays its
highest resources. The caddis worms have theirs, which emerge,
float on the surface, dip down and even stop at mid-depth by
releasing gradually their surplus air. And this apparatus, so
perfectly balanced, so skilful, requires no knowledge on the part
of its constructor. It comes into being of itself, in accordance
with the plans of the universal harmony of things.


I have wished for a few things in my life, none of them capable of
interfering with the common weal. I have longed to possess a pond,
screened from the indiscretion of the passers by, close to my
house, with clumps of rushes and patches of duckweed. Here, in my
leisure hours, in the shade of a willow, I should have meditated
upon aquatic life, a primitive life, easier than our own, simpler
in its affections and its brutalities. I should have watched the
unalloyed happiness of the mollusk, the frolics of the Whirligig,
the figure-skating of the Hydrometra [a water bug known as the Pond
skater], the dives of the Dytiscus beetle, the veering and tacking
of the Notonecta [the water boatman], who, lying on her back, rows
with two long oars, while her short forelegs, folded against her
chest, wait to grab the coming prey. I should have studied the
eggs of the Planorbis, a glairy nebula wherein focuses of life are
condensed even as suns are condensed in the nebulae of the heavens.
I should have admired the nascent creature that turns, slowly turns
in the orb of its egg and describes a volute, the draft, perhaps,
of the future shell. No planet circles round its center of
attraction with greater geometrical accuracy.

I should have brought back a few ideas from my frequent visits to
the pond. Fate decided otherwise: I was not to have my sheet of
water. I have tried the artificial pond, between four panes of
glass. A poor shift! Our laboratory aquariums are not even equal
to the print left in the mud by a mule's hoof, when once a shower
has filled the humble basin and life has stocked it with its

In spring, with the hawthorn in flower and the crickets at their
concerts, a second wish often came to me. Along the road, I light
upon a dead mole, a snake killed with a stone, victims both of
human folly. The mole was draining the soil and purging it of its
vermin. Finding him under his spade, the laborer broke his back
for him and flung him over the hedge. The snake, roused from her
slumber by the soft warmth of April, was coming into the sun to
shed her skin and take on a new one. Man catches sight of her:
'Ah, would you? ' says he. 'See me do something for which the
world will thank me!'

And the harmless beast, our auxiliary in the terrible battle which
husbandry wages against the insect, has its head smashed in and

The two corpses, already decomposing, have begun to smell. Whoever
approaches with eyes that do not see turns away his head and passes
on. The observer stops and lifts the remains with his foot; he
looks. A world is swarming underneath; life is eagerly consuming
the dead. Let us replace matters as they were and leave death's
artisans to their task. They are engaged in a most deserving work.

To know the habits of those creatures charged with the
disappearance of corpses, to see them busy at their work of
disintegration, to follow in detail the process of transmutation
that makes the ruins of what has lived return apace into life's
treasure house: these are things that long haunted my mind. I
regretfully left the mole lying in the dust of the road. I had to
go, after a glance at the corpse and its harvesters. It was not
the place for philosophizing over a stench. What would people say
who passed and saw me!

And what will the reader himself say, if I invite him to that
sight? Surely, to busy one's self with those squalid sextons means
soiling one's eyes and mind? Not so, if you please! Within the
domain of our restless curiosity, two questions stand out above all
others: the question of the beginning and the question of the end.
How does matter unite in order to assume life? How does it
separate when returning to inertia? The pond, with its Planorbis
eggs turning round and round, would have given us a few data for
the first problem; the Mole, going bad under conditions not too
repulsive, will tell us something about the second: he will show us
the working of the crucible wherein all things are melted to begin
anew. A truce to nice delicacy! Odi profanum vulgus et arceo;
hence, ye profane: you would not understand the mighty lesson of
the rag tank.

I am now in a position to realize my second wish. I have space,
air and quiet in the solitude of the harmas. None will come here
to trouble me, to smile or to be shocked at my investigations. So
far, so good; but observe the irony of things: now that I am rid of
passers by, I have to fear my cats, those assiduous prowlers, who,
finding my preparations, will not fail to spoil and scatter them.
In anticipation of their misdeeds, I establish workshops in midair,
whither none but genuine corruption agents can come, flying on
their wings. At different points in the enclosure, I plant reeds,
three by three, which, tied at their free ends, form a stable
tripod. From each of these supports, I hang, at a man's height, an
earthenware pan filled with fine sand and pierced at the bottom
with a hole to allow the water to escape, if it should rain. I
garnish my apparatus with dead bodies. The snake, the lizard, the
toad receive the preference, because of their bare skins, which
enable me better to follow the first attack and the work of the
invaders. I ring the changes with furred and feathered beasts. A
few children of the neighborhood, allured by pennies, are my
regular purveyors. Throughout the good season, they come running
triumphantly to my door, with a snake at the end of a stick, or a
lizard in a cabbage leaf. They bring me the rat caught in a trap,
the chicken dead of the pip, the mole slain by the gardener, the
kitten killed by accident, the rabbit poisoned by some weed. The
business proceeds to the mutual satisfaction of sellers and buyer.
No such trade had ever been known before in the village nor ever
will be again.

April ends; and the pans rapidly fill. An ant, ever so small, is
the first arrival. I thought I should keep this intruder off by
hanging my apparatus high above the ground: she laughs at my
precautions. A few hours after the deposit of the morsel, fresh
still and possessing no appreciable smell, up comes the eager
picker-up of trifles, scales the stems of the tripod in processions
and starts the work of dissection. If the joint suits her, she
even goes to live in the sand of the pan and digs herself temporary
platforms in order to work the rich find more at her ease.

All through the season, from start to finish, she will always be
the promptest, always the first to discover the dead animal, always
the last to beat a retreat when nothing more remains than a heap of
little bones bleached by the sun. How does the vagabond, passing
at a distance, know that, up there, invisible, high on the gibbet,
there is something worth going for? The others, the real knackers,
wait for the meat to go bad; they are informed by the strength of
the effluvia. The ant, gifted with greater powers of scent,
hurries up before there is any stench at all. But, when the meat,
now two days old and ripened by the sun, exhales its flavor, soon
the master ghouls appear upon the scene: Dermestes [bacon beetles,
small flesh-eating beetles] and Saprini [exceedingly small flesh-
eating beetles], Silphae [carrion beetles] and Necrophori [burying
beetles], flies and Staphylini [rove beetles], who attack the
corpse, consume it and reduce it almost to nothing. With the ant
alone, who each time carries off a mere atom, the sanitary
operation would take too long; with them, it is a quick business,
especially as certain of them understand the process of chemical

These last, who are high class scavengers, are entitled to first
mention. They are flies, of many various species. If time
permitted, each of those strenuous ones would deserve a special
examination; but that would weary the patience of both the reader
and the observer. The habits of one will give us a summary notion
of the habits of the rest. We will therefore confine ourselves to
the two principal subjects, namely, the Luciliae, or greenbottles,
and the Sarcophagae, or grey flesh flies.

The Luciliae--flies that glitter--are magnificent flies known to
all of us. Their metallic luster, generally a golden green, rivals
that of our finest beetles, the Rosechafers, Buprestes and leaf
beetles. It gives one a shock of surprise to see so rich a garb
adorn those workers in putrefaction. Three species frequent my
pans: Lucilia Caesar, LIN., L. cadaverina, LIN., and L. cuprea,
ROB. The first two, both of whom are gold-green, are plentiful;
the third, who sports a coppery luster, is rare. All three have
red eyes, set in a silver border.

Lucilia Caesar is larger than L. cadaverina and also more forward
in her business. I catch her in labor on the 23rd of April. She
has settled in the spinal canal of a neck of mutton and is laying
her eggs on the marrow. For more than an hour, motionless in the
gloomy cavity, she goes on packing her eggs. I can just see her
red eyes and her silvery face. At last, she comes out. I gather
the fruit of her labor, an easy matter, for it all lies on the
marrow, which I extract without touching the eggs.

A census would seem important. To take it at once is
impracticable: the germs form a compact mass, which would be
difficult to count. The best thing is to rear the family in a jar
and to reckon by the pupae buried in the sand. I find a hundred
and fifty-seven. This is evidently but a minimum; for Lucilia
Caesar and the others, as the observations that follow will tell
me, lay in packets at repeated intervals. It is a magnificent
family, promising a fabulous legion to come.

The greenbottles, I was saying, break up their laying into
sections. The following scene affords a proof of this. A Mole,
shrunk by a few days' evaporation, lies spread upon the sand of the
pan. At one point, the edge of the belly is raised and forms a
deep arch. Remark that the Greenbottles, like the rest of the
flesh eating flies, do not trust their eggs to uncovered surfaces,
where the heat of the sun's rays might endanger the existence of
the delicate germs. They want dark hiding places. The favorite
spot is the lower side of the dead animal, when this is accessible.

In the present case, the only place of access is the fold formed by
the edge of the belly. It is here and here alone that this day's
mothers are laying. There are eight of them. After exploring the
piece and recognizing its good quality, they disappear under the
arch, first this one, then that, or else several at a time. They
remain under the Mole for a considerable while. Those outside
wait, but go repeatedly to the threshold of the cavern to take a
look at what is happening within and see whether the earlier ones
have finished. These come out at last, perch on the animal and
wait in their turn. Others at once take their place in the
recesses of the cave. They remain there for some time and then,
having done their business, make room for more mothers and come
forth into the sunlight. This going in and out continues
throughout the morning.

We thus learn that the laying is effected by periodical emissions,
broken with intervals of rest. As long as she does not feel ripe
eggs coming to her oviduct, the greenbottle remains in the sun,
hovering to and fro and sipping modest mouthfuls from the carcass.
But, as soon as a fresh stream descends from her ovaries, quick as
lightning she makes for a propitious site whereon to deposit her
burden. It appears to be the work of several days thus to divide
the total laying and to distribute it at different points.

I carefully raise the animal under which these things are
happening. The egg laying mothers do not disturb themselves; they
are far too busy. Their ovipositor extended telescope fashion,
they heap egg upon egg. With the point of their hesitating,
groping instrument, they try to lodge each germ, as it comes,
farther into the mass. Around the serious, red-eyed matrons, the
Ants circle, intent on pillage. Many of them make off with a
greenbottle egg between their teeth. I see some who, greatly
daring, effect their theft under the ovipositor itself. The layers
do not put themselves out, let the ants have their way, remain
impassive. They know their womb to be rich enough to make good any
such larceny.

Indeed, what escapes the depredations of the ants promises a
plenteous brood. Let us come back a few days later and lift the
mole again. Underneath, in a pool of sanies, is a surging mass of
swarming sterns and pointed heads, which emerge, wriggle and dive
in again. It suggests a seething billow. It turns one's stomach.
It is horrible, most horrible. Let us steel ourselves against the
sight: it will be worse elsewhere.

Here is a fat snake. Rolled into a compact whorl, she fills the
whole pan. The greenbottles are plentiful. New ones arrive at
every moment and, without quarrel or strife, take their place among
the others, busily laying. The spiral furrow left by the reptile's
curves is the favorite spot. Here alone, in the narrow space
between the folds, are shelters against the heat of the sun. The
glistening Flies take their places, side by side, in rows; they
strive to push their abdomen and their ovipositor as far forward as
possible, at the risk of rumpling their wings and cocking them
towards their heads. The care of the person is neglected amid this
serious business. Placidly, with their red eyes turned outwards,
they form a continuous cordon. Here and there, at intervals, the
rank is broken; layers leave their posts, come and walk about upon
the snake, what time their ovaries ripen for another emission, and
then hurry back, slip into the rank and resume the flow of germs.
Despite these interruptions, the work of breeding goes fast. In
the course of one morning, the depths of the spiral furrow are hung
with a continuous white bark, the heaped up eggs. They come off in
great slabs, free of any stain; they can be shoveled up, as it
were, with a paper scoop. It is a propitious moment if we wish to
follow the evolution at close quarters. I therefore gather a
profusion of this white manna and lodge it in glass tubes, test
tubes and jars, with the necessary provisions.

The eggs, about a millimeter long, are smooth cylinders, rounded at
both ends. They hatch within twenty-four hours. The first
question that presents itself is this: how do the greenbottle grubs
feed? I know quite well what to give them, but I do not in the
least see how they manage to consume it. Do they eat, in the
strict sense of the word? I have reasons to doubt it.

Let us consider the grub grown to a sufficient size. It is the
usual fly larva, the common maggot, shaped like an elongated cone,
pointed in front, truncated behind, where two little red spots
show, level with the skin: these are the breathing holes. The
front, which is called the head by stretching a word--for it is
little more than the entrance to an intestine--the front is armed
with two little black hooks, which slide in a translucent sheath,
project a little way outside and go in turn by turn. Are we to
look upon these as mandibles? Not at all, for, instead of having
their points facing each other, as would be required in a real
mandibular apparatus, the two hooks work in parallel directions and
never meet. What they are is ambulatory organs, grapnels assisting
locomotion, which give a purchase on the plane and enable the
animal to advance by means of repeated contractions. The maggot
walks with the aid of what a superficial examination would
pronounce to be a machine for eating. It carries in its gullet the
equivalent of the climber's alpenstock.

Let us hold it, on a piece of flesh, under the lens. We shall see
it walking about, raising and lowering its head and, each time,
stabbing the meat with its pair of hooks. When stationary, with
its crupper at rest, it explores space with a continual bending of
its fore part; its pointed head pokes about, jabs forward, goes
back again, producing and withdrawing its black mechanism. There
is a perpetual piston play. Well, look as carefully and
conscientiously as I please, I do not once see the weapons of the
mouth tackle a particle of flesh that is torn away and swallowed.
The hooks come down upon the meat at every moment, but never take a
visible mouthful from it. Nevertheless, the grub waxes big and
fat. How does this singular consumer, who feeds without eating,
set about it? If he does not eat, he must drink; his diet is soup.
As meat is a compact substance, which does not liquefy of its own
accord, there must, in that case, be a certain recipe to dissolve
it into a fluid broth. Let us try to surprise the maggot's secret.

In a glass tube, sealed at one end, I insert a piece of lean flesh,
the size of a walnut, which I have drained of its juices by
squeezing it in blotting paper. On the top of this, I place a few
slabs of greenbottle eggs collected a moment ago from the snake in
my earthen pan. The number of germs is, roughly, two hundred. I
close the tube with a cotton plug, stand it upright, in a shady
corner of my study, and leave things to take their course. A
control tube, prepared like the first, but not stocked with
maggots, is placed beside it.

As early as two or three days after the hatching, I obtain a
striking result. The meat, which was thoroughly drained by the
blotting paper, has become so moist that the young vermin leave a
wet mark behind them as they crawl over the glass. The swarming
brood creates a sort of mist with the crossing and criss-crossing
of its trails. The control tube, on the contrary, keeps dry,
proving that the moisture in which the worms move is not due to a
mere exudation from the meat.

Besides, the work of the maggot becomes more and more evident.
Gradually, the flesh flows in every direction like an icicle placed
before the fire. Soon, the liquefaction is complete. What we see
is no longer meat, but fluid Liebig's extract. If I overturned the
tube, not a drop of it would remain.

Let us clear our minds of any idea of solution by putrefaction, for
in the second tube a piece of meat of the same kind and size has
remained, save for color and smell, what it was at the start. It
was a lump and it is a lump, whereas the piece treated by the worms
runs like melted butter. Here we have maggot chemistry able to
rouse the envy of physiologists when studying the action of the
gastric juice.

I obtain better results still with hard-boiled white of egg. When
cut into pieces the size of a hazel nut and handed over to the
greenbottle's grubs, the coagulated albumen dissolves into a
colorless liquid which the eye might mistake for water. The
fluidity becomes so great that, for lack of a support, the worms
perish by drowning in the broth; they are suffocated by the
immersion of their hind part, with its open breathing holes. On a
denser liquid, they would have kept at the surface; on this, they

A control tube, filled in the same way, but not colonized, stands
beside that in which the strange liquefaction takes place. The
hardboiled white of egg retains its original appearance and
consistency. In course of time, it dries up, if it does not turn
moldy; and that is all.

The other quaternary compounds performing the same functions as
albumen--the gluten of cereals, the fibrin of blood, the casein of
cheese and the legumin of chickpeas--undergo a similar
modification, in varying degrees. Fed, from the moment of leaving
the egg, on any one of these substances, the worms thrive very
well, provided that they escape drowning when the gruel becomes too
clear; they would not fare better on a corpse. And, as a general
rule, there is not much danger of going under: the matter only half
liquefies; it becomes a running pea soup, rather than an actual

Even in this imperfect case, it is obvious that the greenbottle
grubs begin by liquefying their food. Incapable of taking solid
nourishment, they first transform the spoil into running matter;
then, dipping their heads into the product, they drink, they slake
their thirst, with long sups. Their dissolvent, comparable in its
effects with the gastric juice of the higher animals, is, beyond a
doubt, emitted through the mouth. The piston of the hooks,
continually in movement, never ceases spitting it out in
infinitesimal doses. Each spot touched receives a grain of some
subtle pepsin, which soon suffices to make that spot run in every
direction. As digesting, when all is said, merely means
liquefying, it is no paradox to assert that the maggot digests its
food before swallowing it.

These experiments with my filthy, evil smelling tubes have given me
some delightful moments. The worthy Abbe Spallanzani must have
known some such when he saw pieces of raw meat begin to run under
the action of the gastric juice which he took, with pellets of
sponge, from the stomachs of crows. He discovered the secrets of
digestion; he realized in a glass tube the hitherto unknown labors
of gastric chemistry. I, his distant disciple, behold once more,
under a most unexpected aspect, what struck the Italian scientist
so forcibly. Worms take the place of the crows. They slaver upon
meat, gluten, albumen; and those substances turn to fluid. What
our stomach does within its mysterious recesses the maggot achieves
outside, in the open air. It first digests and then imbibes.

When we see it plunging into the carrion broth, we even wonder if
it cannot feed itself, at least to some extent, in a more direct
fashion. Why should not its skin, which is one of the most
delicate, be capable of absorbing? I have seen the egg of the
sacred beetle and other dung beetles growing considerably larger--I
should like to say, feeding--in the thick atmosphere of the
hatching chamber. Nothing tells us that the grub of the
greenbottle does not adopt this method of growing. I picture it
capable of feeding all over the surface of its body. To the gruel
absorbed by the mouth it adds the balance of what is gathered and
strained through the skin. This would explain the need for
provisions liquefied beforehand.

Let us give one last proof of this preliminary liquefaction. If
the carcass--mole, snake or another--left in the open air have a
wire gauze cover placed over it, to keep out the flies, the game
dries under a hot sun and shrivels up without appreciably wetting
the sand on which it lies. Fluids come from it, certainly, for
every organized body is a sponge swollen with water; but the liquid
discharge is so slow and restricted in quantity that the heat and
the dryness of the air disperse it as it appears, while the
underlying sand remains dry, or very nearly so. The carcass
becomes a sapless mummy, a mere bit of leather. On the other hand,
do not use the wire gauze cover, let the flies do their work
unimpeded; and things forthwith assume another aspect. In three or
four days, an oozing sanies appears under the animal and soaks the
sand to some distance.

I shall never forget the striking spectacle with which I conclude
this chapter. This time, the dish is a magnificent Aesculapius'
snake, a yard and a half long and as thick as a wide bottleneck.
Because of its size, which exceeds the dimensions of my pan, I roll
the reptile in a double spiral, or in two storeys. When the
copious joint is in full process of dissolution, the pan becomes a
puddle wherein wallow, in countless numbers, the grubs of the
greenbottle and those of Sarcophaga carnaria, the Grey or checkered
flesh fly, which are even mightier liquefiers. All the sand in the
apparatus is saturated, has turned into mud, as though there had
been a shower of rain. Through the hole at the bottom, which is
protected by a flat pebble, the gruel trickles drop by drop. It is
a still at work, a mortuary still, in which the Snake is being
drawn off. Wait a week or two; and the whole will have
disappeared, drunk up by the sun: naught but the scales and bones
will remain on a sheet of mud.

To conclude: the maggot is a power in this world. To give back to
life, with all speed, the remains of that which has lived, it
macerates and condenses corpses, distilling them into an essence
wherewith the earth, the plant's foster mother, may be nourished
and enriched.


Here the costume changes, not the manner of life. We find the same
frequenting of dead bodies, the same capacity for the speedy
liquefaction of the fleshy matter. I am speaking of an ash-gray
fly, the greenbottle's superior in size, with brown streaks on her
back and silver gleams on her abdomen. Note also the blood-red
eyes, with the hard look of the knacker in them. The language of
science knows her as Sarcophaga, the flesh eater; in the vulgar
tongue she is the grey flesh fly, or simply the flesh fly.

Let not these expressions, however accurate, mislead us into
believing for a moment that the Sarcophagae are the bold company of
master tainters who haunt our dwellings, more particularly in
autumn, and plant their vermin in our ill-guarded viands. The
author of those offences is Calliphora vomitoria, the bluebottle,
who is of a stouter build and arrayed in darkest blue. It is she
who buzzes against our windowpanes, who craftily besieges the meat
safe and who lies in wait in the darkness for an opportunity to
outwit our vigilance. The other, the grey fly, works jointly with
the greenbottles, who do not venture inside our houses and who work
in the sunlight. Less timid, however, than they, should the
outdoor yield be small, she will sometimes come indoors to
perpetrate her villainies. When her business is done, she makes
off as fast as she can, for she does not feel at home with us.

At this moment, my study, a very modest extension of my open air
establishments, has become something of a charnel house. The grey
fly pays me a visit. If I lay a piece of butcher's meat on the
windowsill, she hastens up, works her will on it and retires. No
hiding place escapes her notice among the jars, cups, glasses and
receptacles of every kind with which my shelves are crowded.

With a view to certain experiments, I collected a heap of wasp
grubs, asphyxiated in their underground nests. Stealthily she
arrives, discovers the fat pile and, hailing as treasure trove this
provender whereof her race perhaps has never made use before,
entrusts to it an installment of her family. I have left at the
bottom of a glass the best part of a hard-boiled egg from which I
have taken a few bits of white intended for the greenbottle
maggots. The grey fly takes possession of the remains, recks not
of their novelty and colonizes them. Everything suits her that
falls within the category of albuminous matters: everything, down
to dead silkworms; everything, down to a mess of kidney-beans and

Nevertheless, her preference is for the corpse: furred beast and
feathered beast, reptile and fish, indifferently. Together with
the greenbottles, she is sedulous in her attendance on my pans.
Daily she visits my snakes, takes note of the condition of each of
them, savors them with her proboscis, goes away, comes back, takes
her time and at last proceeds to business. Still, it is not here,
amid the tumult of callers, that I propose to follow her
operations. A lump of butcher's meat laid on the window sill, in
front of my writing table, will be less offensive to the eye and
will facilitate my observations.

Two flies of the genus Sarcophaga frequent my slaughter yard:
Sarcophaga carnaria and Sarcophaga haemorrhoidalis, whose abdomen
ends in a red speck. The first species, which is a little larger
than the second, is more numerous and does the best part of the
work in the open air shambles of the pans. It is this fly also
who, at intervals and nearly always alone, hastens to the bait
exposed on the windowsill.

She comes up suddenly, timidly. Soon she calms herself and no
longer thinks of fleeing when I draw near, for the dish suits her.
She is surprisingly quick about her work. Twice over--buzz! Buzz!-
-the tip of her abdomen touches the meat; and the thing is done: a
group of vermin wriggles out, releases itself and disperses so
nimbly that I have no time to take my lens and count then
accurately. As seen by the naked eye, there were a dozen of them.
What has become of them? One would think that they had gone into
the flesh, at the very spot where they were laid, so quickly have
they disappeared. But that dive into a substance of some
consistency is impossible to these newborn weaklings. Where are
they? I find them more or less everywhere in the creases of the
meat; singly and already groping with their mouths. To collect
them in order to number them is not practicable, for I do not want
to damage them. Let us be satisfied with the estimate made at a
rapid glance: there are a dozen or so, brought into the world in
one discharge of almost inappreciable length.

Those live grubs, taking the place of the usual eggs, have long
been known. Everybody is aware that the flesh flies bring forth
living maggots, instead of laying eggs. They have so much to do
and their work is so urgent! To them, the instruments of the
transformation of dead matter, a day means a day, a long space of
time which it is all important to utilize. The greenbottle's eggs,
though these are of very rapid development, take twenty-four hours
to yield their grubs. The flesh flies save all this time. From
their matrix, laborers flow straightway and set to work the moment
they are born. With these ardent pioneers of sanitation, there is
no rest attendant upon the hatching, there is not a minute lost.

The gang, it is true, is not a numerous one; but how often can it
not be renewed! Read Reaumur's description of the wonderful
procreating machinery boasted by the Flesh flies. It is a spiral
ribbon, a velvety scroll whose nap is a sort of fleece of maggots
set closely together and each cased in a sheath. The patient
biographer counted the host: it numbers, he tells us, nearly twenty
thousand. You are seized with stupefaction at this anatomical

How does the gray fly find the time to settle a family of such
dimensions, especially in small packets, as she has just done on my
window sill? What a number of dead dogs, moles and snakes must she
not visit before exhausting her womb! Will she find them? Corpses
of much size do not abound to that extent in the country. As
everything suits her, she will alight on other remains of minor
importance. Should the prize be a rich one, she will return to it
tomorrow, the day after and later still, over and over again. In
the course of the season, by dint of packets of grubs deposited
here, there and everywhere, she will perhaps end by housing her
entire brood. But then, if all things prosper, what a glut, for
there are several families born during the year! We feel it
instinctively: there must be a check to these generative
Let us first consider the grub. It is a sturdy maggot, easy to
distinguish from the greenbottle's by its larger girth and
especially by the way in which its body terminates behind. There
is here a sudden breaking off, hollowed into a deep cup. At the
bottom of this crater are two breathing holes, two stigmata with
amber-red tips. The edge of the cavity is fringed with half a
score of pointed, fleshy festoons, which diverge like the spikes of
a coronet. The creature can close or open this diadem at will by
bringing the denticulations together or by spreading them out wide.
This protects the air holes which might otherwise be choked up when
the maggot disappears in the sea of broth. Asphyxia would
supervene, if the two breathing holes at the back became
obstructed. During the immersion, the festooned coronet shuts like
a flower closing its petals and the liquid is not admitted to the

Next follows the emergence. The hind part reappears in the air,
but appears alone, just at the level of the fluid. Then the
coronet spreads out afresh, the cup gapes and assumes the aspect of
a tiny flower, with the white denticulations for petals and the two
bright red dots, the stigmata at the bottom, for stamens. When the
grubs, pressed one against the other, with their heads downwards in
the fetid soup, make an unbroken shoal, the sight of those
breathing cups incessantly opening and closing, with a little clack
like a valve, almost makes one forget the horrors of the charnel
yard. It suggests a carpet of tiny Sea anemones. The maggot has
its beauties after all.

It is obvious, if there be any logic in things, that a grub so
well-protected against asphyxiation by drowning must frequent
liquid surroundings. One does not encircle one's hindquarters with
a coronet for the sole satisfaction of displaying it. With its
apparatus of spokes, the Grey Fly's grub informs us of the
dangerous nature of its functions: when working upon a corpse, it
runs the risk of drowning. How is that? Remember the grubs of the
greenbottle, fed on hard-boiled white of egg. The dish suits them;
only, by the action of their pepsin, it becomes so fluid that they
die submerged. Because of their hinder stigmata, which are
actually on the skin and devoid of any defensive machinery, they
perish when they find no support apart from the liquid.

The flesh fly's maggots, though incomparable liquefiers, know
nothing of this peril, even in a puddle of carrion broth. Their
bulky hind part serves as a float and keeps the air holes above the
surface. When, for further investigation, they must needs go under
completely, the anemone at the back shuts and protects the
stigmata. The grubs of the gray fly are endowed with a life buoy
because they are first class liquefiers, ready to incur the danger
of a ducking at any moment.

When high and dry on the sheet of cardboard where I place them to
observe them at my ease, they move about actively, with their
breathing rose widespread and their stigmata rising and falling as
a support. The cardboard is on my table, at three steps from an
open window, and lit at this time of day only by the soft light of
the sky. Well, the maggots, one and all of them, turn in the
opposite direction to the window; they hastily, madly take to

I turn the cardboard round, without touching the runaways. This
action makes the creatures face the light again. Forthwith, the
troop stops, hesitates, takes a half turn and once more retreats
towards the darkness. Before the end of the racecourse is reached,
I again turn the cardboard. For the second time, the maggots veer
round and retrace their steps. Repeat the experiment as often as I
will, each time the squad wheels about in the opposite direction to
the window and persists in avoiding the trap of the revolving

The track is only a short one: the cardboard measures three hand's
breadths in length. Let us give more space. I settle the grubs on
the floor of the room; with a hair pencil, I turn them with their
heads pointing towards the lighted aperture. The moment they are
free, they turn and run from the light. With all the speed whereof
their cripple's shuffle allows, they cover the tiled floor of the
study and go and knock their heads against the wall, twelve feet
off, skirting it afterwards, some to the right and some to the
left. They never feel far enough away from that hateful
illuminated opening.

What they are escaping from is evidently the light, for, if I make
it dark with a screen, the troop does not change its direction when
I turn the cardboard. It then progresses quite readily towards the
window; but, when I remove the screen, it turns tail at once.

That a grub destined to live in the darkness, under the shelter of
a corpse, should avoid the light is only natural; the strange part
is its very perception. The maggot is blind. Its pointed fore
part, which we hesitate to call a head, bears absolutely no trace
of any optical apparatus; and the same with every other part of the
body. There is nothing but one bare, smooth, white skin. And this
sightless creature, deprived of any special nervous points served
by ocular power, is extremely sensitive to the light. Its whole
skin is a sort of retina, incapable of seeing, of course, but able,
at any rate, to distinguish between light and darkness. Under the
direct rays of a searching sun, the grub's distress could be easily
explained. We ourselves; with our coarse skin, in comparison with
that of the maggot, can distinguish between sunshine and shadow
without the help of the eyes. But, in the present case, the
problem becomes singularly complicated. The subjects of my
experiment receive only the diffused light of the sky, entering my
study through an open window; yet this tempered light frightens
them out of their senses. They flee the painful apparition; they
are bent upon escaping at all costs.

Now what do the fugitives feel? Are they physically hurt by the
chemical radiations? Are they exasperated by other radiations,
known or unknown? Light still keeps many a secret hidden from us
and perhaps our optical science, by studying the maggot, might
become the richer by some valuable information. I would gladly
have gone farther into the question, had I possessed the necessary
apparatus. But I have not, I never have had and of course I never
shall have the resources which are so useful to the seeker. These
are reserved for the clever people who care more for lucrative
posts than for fair truths. Let us continue, however, within the
measure which the poverty of my means permits.

When duly fattened, the grubs of the flesh flies go underground to
transform themselves into pupae. The burial is intended,
obviously, to give the worm the tranquillity necessary for the
metamorphosis. Let us add that another object of the descent is to
avoid the importunities of the light. The maggot isolates itself
to the best of its power and withdraws from the garish day before
contracting into a little keg. In ordinary conditions, with a
loose soil, it goes hardly lower than a hand's breadth down, for
provision has to be made for the difficulties of the return to the
surface when the insect, now full grown, is impeded by its delicate
fly wings. The grub, therefore, deems itself suitably isolated at
a moderate depth. Sideways, the layer that shields it from the
light is of indefinite thickness; upwards, it measures about four
inches. Behind this screen reigns utter darkness, the buried one's
delight. This is capital.

What would happen if, by an artifice, the sideward layer were
nowhere thick enough to satisfy the grub? Now, this time, I have
the wherewithal to solve the problem, in the shape of a big glass
tube, open at both ends, about three feet long and less than an
inch wide. I use it to blow the flame of hydrogen in the little
chemistry lessons which I give my children.

I close one end with a cork and fill the tube with fine, dry,
sifted sand. On the surface of this long column, suspended
perpendicularly in a corner of my study, I install some twenty
Sarcophaga grubs, feeding them with meat. A similar preparation is
repeated in a wider jar, with a mouth as broad as one's hand. When
they are big enough, the grubs in either apparatus will go down to
the depth that suits them. There is no more to be done but to
leave them to their own devices.

The worms at last bury themselves and harden into pupae. This is
the moment to consult the two apparatus. The jar gives me the
answer which I should have obtained in the open fields. Four
inches down, or thereabouts, the worms have found a quiet lodging,
protected above by the layer through which they have passed and on
every side by the thickness of the vessel's contents. Satisfied
with the site, they have stopped there.

It is a very different matter in the tube. The least buried of the
pupae are half a yard down. Others are lower still; most of them
even have reached the bottom of the tube and are touching the cork
stopper, an insuperable barrier. These last, we can see, would
have gone yet deeper if the apparatus had allowed them. Not one of
the score of grubs has settled at the customary halting place; all
have traveled farther down the column, until their strength gave
way. In their anxious flight, they have dug deeper and ever

What were they flying from? The light. Above them, the column
traversed forms a more than sufficient shelter; but, at the sides,
the irksome sensation is still felt through a coat of earth half an
inch thick if the descent is made perpendicularly. To escape the
disturbing impression, the grub therefore goes deeper and deeper,
hoping to obtain lower down the rest which is denied it above. It
only ceases to move when worn out with the effort or stopped by an

Now, in a soft diffused light, what can be the radiations capable
of acting upon this lover of darkness? They are certainly not the
simple luminous rays, for a screen of fine, heaped up earth, nearly
half an inch in thickness, is perfectly opaque. Then, to alarm the
grub, to warn it of the over proximity of the exterior and send it
to mad depths in search of isolation, other radiations, known or
unknown, must be required, radiations capable of penetrating a
screen against which ordinary radiations are powerless. Who knows
what vistas the natural philosophy of the maggot might open out to
us? For lack of apparatus, I confine myself to suspicions.

To go underground to a yard's depth--and farther if my tube had
allowed it--is on the part of the Flesh fly's grub a vagary
provoked by unkind experiment: never would it bury itself so low
down, if left to its own wisdom. A hand's breadth thickness is
quite enough, is even a great deal when, after completing the
transformation, it has to climb back to the surface, a laborious
operation absolutely resembling the task of an entombed well
sinker. It will have to fight against the sand that slips and
gradually fills up the small amount of empty space obtained; it
will perhaps, without crowbar or pickaxe, have to cut itself a
gallery through something tantamount to tufa, that is to say,
through earth which a shower has rendered compact. For the
descent, the grub has its fangs; for the assent, the fly has
nothing. Only that moment come into existence, she is a weakling,
with tissues still devoid of any firmness. How does she manage to
get out? We shall know by watching a few pupae placed at the
bottom of a test-tube filled with earth. The method of the Flesh
flies will teach us that of the greenbottles and the other Flies,
all of whom make use of the same means.

Enclosed in her pupa, the nascent fly begins by bursting the lid of
her casket with a hernia which comes between her two eyes and
doubles or trebles the size of her head. This cephalic blister
throbs: it swells and subsides by turns, owing to the alternate
flux and reflux of the blood. It is like the piston of an
hydraulic press opening and forcing back the front part of the keg.

The head makes its appearance. The hydrocephalous monster
continues the play of her forehead, while herself remaining
stationary. Inside the pupa, a delicate work is being performed:
the casting of the white nymphal tunic. All through this
operation, the hernia is still projecting. The head is not the
head of a fly, but a queer, enormous mitre, spreading at the base
into two red skull caps, which are the eyes. To split her cranium
in the middle, shunt the two halves to the right and left and send
surging through the gap a tumor which staves the barrel with its
pressure: this constitutes the Fly's eccentric method.

For what reason does the hernia, once the keg is staved, continue
swollen and projecting? I take it to be a waste pocket into which
the insect momentarily forces back its reserves of blood in order
to diminish the bulk of the body to that extent and to extract it
more easily from the nymphal slough and afterwards from the narrow
channel of the shell. As long as the operation of the release
lasts, it pushes outside all that it is able to inject of its
accumulated humors; it makes itself small inside the pupa and
swells into a bloated deformity without. Two hours and more are
spent in this laborious stripping.

At last, the fly comes into view. The wings, mere scanty stumps,
hardly reach the middle of the abdomen. On the outer edge, they
have a deep notch similar to the waist of a violin. This
diminishes by just so much the surface and the length, an excellent
device for decreasing the friction along the earthy column which
has next to be scaled. The hydrocephalous one resumes her
performance more vigorously than ever; she inflates and deflates
her frontal knob. The pounded sand rustles down the insect's
sides. The legs play but a secondary part. Stretched behind,
motionless, when the piston stroke is delivered, they furnish a
support. As the sand descends, they pile it and nimbly push it
back, after which they drag along lifelessly until the next
avalanche. The head advances each time by a length equal to that
of the sand displaced. Each stroke of the frontal swelling means a
step forward. In a dry, loose soil, things go pretty fast. A
column six inches high is traversed in less than a quarter of an

As soon as it reaches the surface, the insect, covered with dust,
proceeds to make its toilet. It thrusts out the blister of its
forehead for the last time and brushes it carefully with its front
tarsi. It is important that the little pounding engine should be
carefully dusted before it is taken inside to form a forehead that
will open no more: this lest any grit should lodge in the head.
The wings are carefully brushed and polished; they lose their
curved notches; they lengthen and spread. Then, motionless on the
surface of the sand, the fly matures fully. Let us set her at
liberty. She will go and join the others on the Snakes in my pans.


Underneath the wasp's brown paper manor house, the ground is
channeled into a sort of drain for the refuse of the nest. Here
are shot the dead or weakly larvae which a continual inspection
roots out from the cells to make room for fresh occupants; here, at
the time of the autumn massacre, are flung the backward grubs;
here, lastly, lies a good part of the crowd killed by the first
touch of winter. During the rack and ruin of November and
December, this sewer becomes crammed with animal matter.

Such riches will not remain unemployed. The world's great law
which says that nothing edible shall be wasted provides for the
consumption of a mere ball of hair disgorged by the owl. How shall
it be with the vast stores of a ruined wasps' nest! If they have
not come yet, the consumers whose task it is to salve this abundant
wreckage for nature's markets, they will not tarry in coming and
waiting for the manna that will soon descend from above. That
public granary, lavishly stocked by death, will become a busy
factory of fresh life. Who are the guests summoned to the banquet?

If the wasps flew away, carrying the dead or sickly grubs with
them, and dropped them on the ground round about their home, those
banqueters would be, first and foremost, the insect-eating birds,
the warblers, all of whom are lovers of small game. In this
connection, we will allow ourselves a brief digression. We all
know with what jealous intolerance the nightingales occupy each his
own cantonment. Neighborly intercourse among them is tabooed. The
males frequently exchange defiant couplets at a distance; but,
should the challenged party draw near, the challenger makes him
clear off. Now, not far from my house, in a scanty clump of holly
oaks which would barely give the woodcutter the wherewithal for a
dozen faggots, I used, all through the spring, to hear such full-
throated warbling of nightingales that the songs of those virtuosi,
all giving voice at once and with no attempt at order, degenerated
into a deafening hubbub.

Why did those passionate devotees of solitude come and settle in
such large numbers at a spot where custom decrees that there is
just room enough for one household only? What reasons have made
the recluse become a congregation? I asked the owner of the
spinney about the matter.

'It's like that every year,' he said. 'The clump is overrun by

'And the reason? '

'The reason is that there is a hive close by, behind that wall.'

I looked at the man in amazement, unable to understand what
connection there could be between a hive and the thronging

'Why, yes,' he added, 'there are a lot of nightingales because
there are a lot of bees.

Another questioning look from my side. I did not yet understand.
The explanation came: 'The bees,' he said, 'throw out their dead
grubs. The front of the hive is strewn with them in the mornings;
and the nightingales come and collect them for themselves and their
families. They are very fond of them.'

This time I had solved the puzzle. Delicious food, abundant and
fresh each day, had brought the songsters together. Contrary to
their habit, numbers of nightingales are living on friendly terms
in a cluster of bushes, in order to be near the hive and to have a
larger share in the morning distribution of plump dainties.

In the same way, the nightingale and his gastronomical rivals would
haunt the neighborhood of the wasps' nests, if the dead grubs were
cast out on the surface of the soil; but these delicacies fall
inside the burrow and no little bird would dare to enter the murky
cave, even if the entrance were not too small to admit it. Other
consumers are needed here, small in size and great in daring; the
fly is called for and her maggot, the king of the departed. What
the greenbottles, the bluebottles and the flesh flies do in the
open air, at the expense of every kind of corpse, other flies,
narrowing their province, do underground at the Wasps' expense.

Let us turn our attention, in September, to the wrapper of a wasps'
nest. On the outer surface and there alone, this wrapper is strewn
with a multitude of big, white, elliptical dots, firmly fixed to
the brown paper and measuring about two millimeters and a half long
by one and a half wide. Flat below, convex above and of a lustrous
white, these dots resemble very neat drops fallen from a tallow
candle. Lastly, their backs are streaked with faint transversal
lines, an elegant detail perceptible only with the lens. These
curious objects are scattered all over the surface of the wrapper,
sometimes at a distance from one another, sometimes gathered into
more or less dense groups. They are the eggs of the Volucella, or
bumblebee fly (Volucella zonaria, LIN.)

Also stuck to the brown paper of the outer wrapper and mixed up
with the Volucella's are a large number of other eggs, chalk white,
spear-shaped and ridged lengthwise with seven or eight thin ribs,
after the manner of the seeds of certain Umbelliferae. The
finishing touch to their delicate beauty is the fine stippling all
over the surface. They are smaller by half than the others. I
have seen grubs come out of them which might easily be the earliest
stage of some pointed maggots which I have already noticed in the
burrows. My attempts to rear them failed; and I am not able to say
which fly these eggs belong to. Enough for us to note the nameless
one in passing. There are plenty of others, which we must make up
our minds to leave unlabelled, in view of the jumbled crowd of
feasters in the ruined wasps' nest. We will concern ourselves only
with the most remarkable, in the front rank of which stands the
bumblebee Fly.

She is a gorgeous and powerful fly; and her costume, with its brown
and yellow bands, shows a vague resemblance to that of the wasps.
Our fashionable theorists have availed themselves of this brown and
yellow to cite the Volucella as a striking instance of protective
mimicry. Obliged, if not on her own behalf, at least on that of
her family, to introduce herself as a parasite into the wasp's
home, she resorts, they tell us, to trickery and craftily dons her
victim's livery. Once inside the wasps' nest, she is taken for one
of the inhabitants and attends quietly to her business.

The simplicity of the wasp, duped by a very clumsy imitation of her
garb, and the depravity of the fly, concealing her identity under a
counterfeit presentment, exceed the limits of my credulity. The
wasp is not so silly nor the Volucella so clever as we are assured.
If the latter really meant to deceive the Wasp by her appearance,
we must admit that her disguise is none too successful. Yellow
sashes round the abdomen do not make a wasp. It would need more
than that and, above all, a slender figure and a nimble carriage;
and the Volucella is thickset and corpulent and sedate in her
movements. Never will the wasp take that unwieldy insect for one
of her own kind. The difference is too great.

Poor Volucella, mimesis has not taught you enough. You ought--this
is the essential point--to have adopted a wasp's shape; and that
you forgot to do: you remained a fat fly, easily recognizable.
Nevertheless, you penetrate into the terrible cavern; you are able
to stay there for a long time, without danger, as the eggs
profusely strewn on the wrapper of the wasps' nest show. How do
you set about it?

Let us, first of all, remember that the bumblebee fly does not
enter the enclosure in which the combs are heaped: she keeps to the
outer surface of the paper rampart and there lays her eggs. Let
us, on the other hand, recall the Polistes [a tree nesting wasp]
placed in the company of the wasps in my vivarium. Here of a
surety is one who need not have recourse to mimicry to find
acceptance. She belongs to the guild, she is a wasp herself. Any
of us that had not the trained eye of the entomologist would
confuse the two species. Well, this stranger, as long as she does
not become too importunate, is quite readily tolerated by the caged
wasps. None seeks to pick a quarrel with her. She is even
admitted to the table, the strip of paper smeared with honey. But
she is doomed if she inadvertently sets foot upon the combs. Her
costume, her shape, her size, which tally almost exactly with the
costume, shape and size of the wasp, do not save her from her fate.
She is at once recognized as a stranger and attacked and
slaughtered with the same vigor as the larvae of the Hylotoma
sawfly and the Saperda beetle, neither of which bears any outward
resemblance to the larva of the wasps.

Seeing that identity of shape and costume does not save the
Polistes, how will the Volucella fare, with her clumsy imitation?
The wasp's eye, which is able to discern the dissimilar in the
like, will refuse to be caught. The moment she is recognized, the
stranger is killed on the spot. As to that there is not the shadow
of a doubt.

In the absence of bumblebee flies at the moment of experimenting, I
employ another fly, Milesia fulminans, who, thanks to her slim
figure and her handsome yellow bands, presents a much more striking
likeness to the wasp than does the fat Volucella zonaria. Despite
this resemblance, if she rashly venture on the combs, she is
stabbed and slain. Her yellow sashes, her slender abdomen deceive
nobody. The stranger is recognized behind the features of a

My experiments under glass, which varied according to the captures
which I happened to make, all lead me to this conclusion: as long
as there is more propinquity, even around the honey, the other
occupants are tolerated fairly well; but, if they touch the cells,
they are assaulted and often killed, without distinction of shape
or costume. The grubs' dormitory is the sanctum sanctorum which no
outsider must enter under pain of death.

With these caged captives I experiment by daylight, whereas the
free wasps work in the absolute darkness of their underground
retreat. Where light is absent, color goes for nothing. Once,
therefore, that she has entered the cavern, the bumblebee fly
derives no benefit from her yellow bands, which are supposed to be
her safeguard. Whether garbed as she is or otherwise, it is easy
for her to effect her purpose in the dark, on condition that she
avoids the tumultuous interior of the wasps' nest. So long as she
has the prudence not to hustle the passers by, she can dab her
eggs, without danger, on the paper wall. No one will know of her
presence. The dangerous thing is to cross the threshold of the
burrow in broad daylight, before the eyes of those who go in and
out. At that moment alone, protective mimicry would be convenient.
Now does the entrance of the Volucella into the presence of a few
wasps entail such very great risks? The wasps' nest in my
enclosure, the one which was afterwards to perish in the sun under
a bell glass, gave me the opportunity for prolonged observations,
but without any result upon the subject of my immediate concern.
The bumblebee fly did not appear. The period for her visits had
doubtless passed; for I found plenty of her grubs when the nest was
dug up.

Other flies rewarded me for my assiduity. I saw some--at a
respectful distance, I need hardly say--entering the burrow. They
were insignificant in size and of a dark gray color, not unlike
that of the housefly. They had not a patch of yellow about them
and certainly had no claim to protective mimicry. Nevertheless,
they went in and out as they pleased, calmly, as though they were
at home. As long as there was not too great a number at the door,
the wasps left them alone. When there was anything of a crowd, the
gray visitors waited near the threshold for a less busy moment. No
harm came to them.

Inside the establishment, the same peaceful relations prevail. In
this respect I have the evidence of my excavations. In the
underground charnel house, so rich in Fly grubs, I find no corpses
of adult flies. If the strangers had been slaughtered in passing
through the entrance hall, or lower down, they would fall to the
bottom of the burrow anyhow, with the other rubbish. Now in this
charnel house, as I said, there are never any dead bumblebee flies,
never a fly of any sort. The incomers are respected. Having done
their business, they go out unscathed.

This tolerance on the part of the wasps is surprising. And a
suspicion comes to one's mind: can it be that the Volucella and the
rest are not what the accepted theories of natural history call
them, namely, enemies, grub killers sacking the wasps' nest? We
will look into this by examining them when they are hatched.
Nothing is easier, in September and October, than to collect the
Volucella's eggs in such numbers as we please. They abound on the
outer surface of the wasps' nest. Moreover, as with the larvae of
the wasp, it is some time before they are suffocated by the
petroleum fumes; and so most of them are sure to hatch. I take my
scissors, cut the most densely populated bits from the paper wall
of the nest and fill a jar with them. This is the warehouse from
which I shall daily, for the best part of the next two months, draw
my supply of nascent grubs.

The Volucella's egg remains where it is, with its white color
always strongly marked against the brown of the background. The
shell wrinkles and collapses; and the fore end tears open. From it
there issues a pretty little white grub, thin in front, swelling
slightly in the rear and bristling all over with fleshy
protuberances. The creature's papillae are set on its sides like
the teeth of a comb; at the rear, they lengthen and spread into a
fan; on the back, they are shorter and arranged in four
longitudinal rows. The last section but one carries two short,
bright red breathing tubes, standing aslant and joined to each
other. The fore part, near the pointed mouth, is of a darker,
brownish color. This is the biting and motor apparatus, seen
through the skin and consisting of two fangs. Taken all round, the
grub is a pretty little thing, with its bristling whiteness, which
gives it the appearance of a tiny snowflake. But this elegance
does not last long: grown big and strong, the bumblebee fly's grub
becomes soiled with sanies, turns a russety brown and crawls about
in the guise of a hulking porcupine.

What becomes of it when it leaves the egg? This my warehousing jar
tells me, partly. Unable to keep its balance on sloping surfaces,
it drops to the bottom of the receptacle, where I find it, daily,
as hatched, wandering restlessly. Things must happen likewise at
the wasps'. Incapable of standing on the slant of the paper wall,
the newborn grubs slide to the bottom of the underground cavity,
which contains, especially at the end of the summer, a heaped up
provender of deceased wasps and dead larvae removed from the cells
and flung outside the house, all nice and gamy, as proper maggot's
food should be.
The Volucella's offspring, themselves maggots, notwithstanding
their snowy apparel, find in this charnel house victuals to their
liking, incessantly renewed. Their fall from the high walls might
well be not accidental, but rather a means of reaching, quickly and
without searching, the good things down at the bottom of the
cavern. Perhaps, also, some of the white grubs, thanks to the
holes that make the wrapper resemble a spongy cover, manage to slip
inside the Wasps' nest. Still, most of the Volucella's grubs, at
whatever stage of their development, are in the basement of the
burrow, among the carrion remains. The others, those settled in
the wasps' home itself, are comparatively few.

These returns are enough to show us that the grubs of the bumblebee
fly do not deserve the bad reputation that has been given them.
Satisfied with the spoils of the dead, they do not touch the
living; they do not ravage the wasps' nest: they disinfect it.

Experiment confirms what we have learnt in the actual nests. Over
and over again, I bring wasp grubs and Volucella grubs together in
small test tubes, which are easy to observe. The first are well
and strong; I have just taken them from their cells. The others
are in various stages, from that of the snowflake born the same day
to that of the sturdy porcupine. There is nothing tragic about the
encounter. The grubs of the bumblebee fly roam about the test-tube
without touching the live tidbit. The most that they do is to put
their mouths for a moment to the morsel; then they take it away
again, not caring for the dish.

They want something different: a wounded, a dying grub; a corpse
dissolving into sanies. Indeed, if I prick the wasp grub with a
needle, the scornful ones at once come and sup at the bleeding
wound. If I give them a dead grub, brown with putrefaction, the
worms rip it open and feast on its humors. Better still: I can
feed them quite satisfactorily with wasps that have turned putrid
under their horny rings; I see them greedily suck the juices of
decomposing Rosechafer grubs; I can keep them thriving with chopped
up butcher's meat, which they know how to liquefy by the method of
the common maggot. And these unprejudiced ones, who accept
anything that comes their way, provided it be dead, refuse it when
it is alive. Like the true flies that they are, frank body
snatchers, they wait, before touching a morsel, for death to do its

Inside the wasps' nest, robust grubs are the rule and weaklings the
rare exception, because of the assiduous supervision which
eliminates anything that is diseased and like to die. Here,
nevertheless, Volucella grubs are found, on the combs, among the
busy wasps. They are not, it is true, so numerous as in the
charnel house below, but still pretty frequent. Now what do they
do in this abode where there are no corpses? Do they attack the
healthy? Their continual visits from cell to cell would at first
make one think so; but we shall soon be undeceived if we observe
their movements closely; and this is possible with my glass roofed

I see them fussily crawling on the surface of the combs, curving
their necks from side to side and taking stock of the cells. This
one does not suit, nor that one either; the bristly creature passes
on, still in search, thrusting its pointed fore part now here, now
there. This time, the cell appears to fulfil the requisite
conditions. A larva, glowing with health, opens wide its mouth,
believing its nurse to be approaching. It fills the hexagonal
chamber with its bulging sides.

The gluttonous visitor bends and slides its slender fore part, a
blade of exquisite suppleness, between the wall and the inhabitant,
whose slack rotundity yields to the pressure of this animated
wedge. It plunges into the cell, leaving no part of itself outside
but its wide hind quarters, with the red dots of the two breathing

It remains in this posture for some time, occupied with its work at
the bottom of the cell. Meanwhile, the wasps present do not
interfere, remain impassive, showing that the grub visited is in no
peril. The stranger, in fact, withdraws with a soft, gliding
motion. The chubby babe, a sort of India rubber bag, resumes its
original volume without having suffered any harm, as its appetite
proves. A nurse offers it a mouthful, which it accepts with every
sign of unimpaired vigor. As for the Volucella grub, it licks its
lips after its own fashion, pushing its two fangs in and out; then,
without further loss of time, goes and repeats its probing

What it wants down there, at the bottom of the cells, behind the
grubs, cannot be decided by direct observation; it must be guessed
at. Since the visited larva remains intact, it is not prey that
the Volucella grub is after. Besides, if murder formed part of its
plans, why descend to the bottom of the cell, instead of attacking
the defenseless recluse straight way? It would be much easier to
suck the patient's juices through the actual orifice of the cell.
Instead of that, we see a dip, always a dip and never any other

Then what is there behind the wasp grub? Let us try to put it as
decently as possible. In spite of its exceeding cleanliness, this
grub is not exempt from the physiological ills inseparable from the
stomach. Like all that eats, it has intestinal waste matter with
regard to which its confinement compels it to behave with extreme
discretion. Like so many other close-cabined larvae of Wasps and
Bees, it waits until the moment of the transformation to rid itself
of its digestive refuse. Then, once and for all, it casts out the
unclean accumulation whereof the pupa, that delicate, reborn
organism, must not retain the least trace. This is found later, in
any empty cell, in the form of a dark purple plug. But, without
waiting for this final purge, this lump, there are, from time to
time, slight excretions of fluid, clear as water. We have only to
keep a Wasp grub in a little glass tube to recognize these
occasional discharges. Well, I see nothing else to explain the
action of the Volucella's grubs when they dip into the cells
without wounding the larvae. They are looking for this liquid,
they provoke its emission. It represents to them a dainty which
they enjoy over and above the more substantial fare provided by the

The bumblebee fly, that sanitary inspector of the Vespine city,
fulfils a double office: she wipes the wasp's children and she rids
the nest of its dead. For this reason, she is peacefully received,
as an auxiliary, when she enters the burrow to lay her eggs; for
this reason, her grub is tolerated, nay more, respected, in the
very heart of the dwelling, where none might stray with impunity.
I remember the brutal reception given to the Saperda and Hylotoma
grubs when I place them on a comb. Forthwith grabbed, bruised and
riddled with stings, the poor wretches perish. It is quite a
different matter with the offspring of the Volucella. They come
and go as they please, poke about in the cells, elbow the
inhabitants and remain unmolested. Let us give some instances of
this clemency, which is very strange in the irascible Wasp.

For a couple of hours, I fix my attention on a Volucella grub
established in a cell, side by side with the Wasp grub, the
mistress of the house. The hind quarters emerge, displaying their
papillae. Sometimes also the fore part, the head, shows, bending
from side to side with sudden, snake-like motions. The wasps have
just filled their crops at the honey pot; they are dispensing the
rations, are very busily at work; and things are taking place in
broad daylight, on the table by the window.

As they pass from cell to cell, the nurses repeatedly brush against
and stride across the Volucella grub. There is no doubt that they
see it. The intruder does not budge, or, if trodden on, curls up,
only to reappear the next moment. Some of the wasps stop, bend
their heads over the opening, seem to be making inquiries and then
go off, without troubling further about the state of things. One
of them does something even more remarkable: she tries to give a
mouthful to the lawful occupant of the cell; but the larva, which
is being squeezed by its visitor, has no appetite and refuses.
Without the least sign of anxiety on behalf of the nursling which
she sees in awkward company, the wasp retires and goes to
distribute its ration elsewhere. In vain I prolong my examination:
there is no fluster of any kind. The Volucella grub is treated as
a friend, or at least as a visitor that does not matter. There is
no attempt to dislodge it, to worry it, to put it to flight. Nor
does the grub seem to trouble greatly about those who come and go.
Its tranquillity, tells us that it feels at home.

Here is some further evidence: the grub has plunged, head
downwards, into an empty cell, which is too small to contain the
whole of it. Its hindquarters stick out, very visibly. For long
hours, it remains motionless in this position. At every moment,
wasps pass and repass close by. Three of them, at one time
together, at another separately, come and nibble at the edges of
the cell; they break off particles which they reduce to paste for a
new piece of work. The passers by, intent upon their business, may
not perceive the intruder; but these three certainly do. During
their work of demolition, they touch the grub with their legs,
their antennae, their palpi; and yet none of them minds it. The
fat grub, so easily recognized by its queer figure, is left alone;
and this in broad daylight, where everybody can see it. What must
it be when the profound darkness of the burrows protects the
visitor with its mysteries!

I have been experimenting all along with big Volucella grubs,
colored with the dirty red which comes with age. What effect will
pure white produce? I sprinkle on the surface of the combs some
larvae that have lately left the egg. The tiny, snow-white grubs
make for the nearest cells, go down into them, come out again and
hunt elsewhere. The wasps peaceably let them go their way, as
heedless of the little white invaders as of the big red ones.
Sometimes, when it enters an occupied cell, the little creature is
seized by the owner, the wasp grub, which nabs it and turns and
returns it between its mandibles. Is this a defensive bite? No,
the wasp grub has merely blundered, taking its visitor for a
proffered mouthful. There is no great harm done. Thanks to its
suppleness, the little grub emerges from the grip intact and
continues its investigations.

It might occur to us to attribute this tolerance to some lack of
penetration in the wasps' vision. What follows will undeceive us:
I place separately, in empty cells, a grub of Saperda scalaria and
a Volucella grub, both of them white and selected so as not to fill
the cell entirely. Their presence is revealed only by the paleness
of the hind part which serves as a plug to the opening. A
superficial examination would leave the nature of the recluse
undecided. The wasps make no mistake: they extirpate the Saperda
grub, kill it, fling it on the dust heap; they leave the Volucella
grub in peace.

The two strangers are quite well recognized in the secrecy of the
cells: one is the intruder that must be turned out; the other is
the regular visitor that must be respected. Sight helps, for
things take place in the daylight, under glass; but the wasps have
other means of information in the dimness of the burrow. When I
produce darkness by covering the apparatus with a screen, the
murder of the trespassers is accomplished just the same. For so
say the police regulations of the wasps' nest: any stranger
discovered must be slain and thrown on the midden.

To thwart this vigilance, the real enemies need to be masters of
the art of deceptive immobility and cunning disguise. But there is
no deception about the Volucella grub. It comes and goes, openly,
wheresoever it will; it looks round amongst the wasps for cells to
suit it. What has it to make itself thus respected? Strength?
Certainly not. It is a harmless creature, which the wasp could rip
open with a blow of her shears, while a touch of the sting would
mean lightning death. It is a familiar guest, to whom no denizen
of a wasps' nest bears any ill will. Why? Because it renders good
service: so far from working mischief, it does the scavenging for
its hosts. Were it an enemy or merely an intruder, it would be
exterminated; as a deserving assistant, it is respected.

Then what need is there for the Volucella to disguise herself as a
wasp? Any fly, whether clad in drab or motley, is admitted to the
burrow directly she makes herself useful to the community. The
mimicry of the bumblebee fly, which was said to be one of the most
conclusive cases, is, after all, a mere childish notion. Patient
observation, continually face to face with facts, will have none of
it and leaves it to the armchair naturalists, who are too prone to
look at the animal world through the illusive mists of theory,


The spider's web is a glorious mathematical problem. I should
enjoy working it out in all its details, were I not afraid of
wearying the reader's attention. Perhaps I have even gone too far
in the little that I have said, in which case I owe him some
compensation: 'Would you like me,' I will ask him, 'would you like
me to tell you how I acquired sufficient algebra to master the
logarithmic systems and how I became a surveyor of Spiders' webs?
Would you? It will give us a rest from natural history.'

I seem to catch a sign of acquiescence. The story of my village
school, visited by the chicks and the porkers, has been received
with some indulgence; why should not my harsh school of solitude
possess its interest as well? Let us try to describe it. And who
knows? Perhaps, in doing so, I shall revive the courage of some
other poor derelict hungering after knowledge.

I was denied the privilege of learning with a master. I should be
wrong to complain. Solitary study has its advantages: it does not
cast you in the official mould; it leaves you all your originality.
Wild fruit, when it ripens, has a different taste from hothouse
produce: it leaves on a discriminating palate a bittersweet flavor
whose virtue is all the greater for the contrast. Yes, if it were
in my power, I would start afresh, face to face with my only
counselor, the book itself, not always a very lucid one; I would
gladly resume my lonely watches, my struggles with the darkness
whence, at last, a glimmer appears as I continue to explore it; I
should retraverse the irksome stages of yore, stimulated by the one
desire that has never failed me, the desire of learning and of
afterwards bestowing my mite of knowledge on others.

When I left the normal school, my stock of mathematics was of the
scantiest. How to extract a square root, how to calculate and
prove the surface of a sphere: these represented to me the
culminating points of the subject. Those terrible logarithms, when
I happened to open a table of them, made my head swim, with their
columns of figures; actual fright, not unmixed with respect,
overwhelmed me on the very threshold of that arithmetical cave. Of
algebra I had no knowledge whatever. I had heard the name; and the
syllables represented to my poor brain the whole whirling legion of
the abstruse.

Besides, I felt no inclination to decipher the alarming
hieroglyphics. They made one of those indigestible dishes which we
confidently extol without touching them. I greatly preferred a
fine line of Virgil, whom I was now beginning to understand; and I
should have been surprised indeed had any one told me that, for
long years to come, I should be an enthusiastic student of the
formidable science. Good fortune procured me my first lesson in
algebra, a lesson given and not received, of course.

A young man of about my own age came to me and asked me to teach
him algebra. He was preparing for his examination as a civil
engineer; and he came to me because, ingenuous youth that he was,
he took me for a well of learning. The guileless applicant was
very far out in his reckoning.

His request gave me a shock of surprise, which was forthwith
repressed on reflection: 'I give algebra lessons? ' said I to
myself. 'It would be madness: I don't know anything about the

And I left it at that for a moment or two, thinking hard, drawn now
this way, now that with indecision: 'Shall I accept? Shall I
refuse? ' continued the inner voice.

Pooh, let's accept! An heroic method of learning to swim is to leap
boldly into the sea. Let us hurl ourselves head first into the
algebraical gulf; and perhaps the imminent danger of drowning will
call forth efforts capable of bringing me to land. I know nothing
of what he wants. It makes no difference: let's go ahead and
plunge into the mystery. I shall learn by teaching.

It was a fine courage that drove me full tilt into a province which
I had not yet thought of entering. My twenty-year-old confidence
was an incomparable lever.

'Very well,' I replied. 'Come the day after tomorrow, at five, and
we'll begin.'

This twenty-four hours' delay concealed a plan. It secured me the
respite of a day, the blessed Thursday, which would give me time to
collect my forces.

Thursday comes. The sky is gray and cold. In this horrid weather,
a grate well filled with coke has its charms. Let's warm ourselves
and think.

Well, my boy, you've landed yourself in a nice predicament! How
will you manage tomorrow? With a book, plodding all through the
night, if necessary, you might scrape up something resembling a
lesson, just enough to fill the dread hour more or less. Then you
could see about the next: sufficient for the day is the evil
thereof. But you haven't the book. And it's no use running out to
the bookshop. Algebraical treatises are not current wares. You'll
have to send for one, which will take a fortnight at least. And
I've promised for tomorrow, for tomorrow certain! Another argument
and one that admits of no reply: funds are low; my last pecuniary
resources lie in the corner of a drawer. I count the money: it
amounts to twelve sous, which is not enough.

Must I cry off? Rather not! One resource suggests itself: a highly
improper one, I admit, not far removed indeed from larceny. O
quiet paths of algebra, you are my excuse for this venial sin! Let
me confess the temporary embezzlement.

Life at my college is more or less cloistered. In return for a
modest payment, most of us masters are lodged in the building; and
we take our meals at the principal's table. The science master,
who is the big gun of the staff and lives in the town, has
nevertheless, like ourselves, his own two cells, in addition to a
balcony, or leads, where the chemical preparations give forth their
suffocating gases in the open air. For this reason, he finds it
more convenient to hold his class here during the greater part of
the year. The boys come to these rooms in winter, in front of a
grate stuffed full of coke, like mine, and there find a blackboard,
a pneumatic trough, a mantelpiece covered with glass receivers,
panoplies of bent tubes on the walls, and, lastly, a certain
cupboard in which I remember seeing a row of books, the oracles
consulted by the master in the course of his lessons.

'Among those books,' said I to myself, 'there is sure to be one on
algebra. To ask the owner for the loan of it does not appeal to
me. My amiable colleague would receive me superciliously and laugh
at my ambitious aims. I am sure he would refuse my request.'

The future was to show that my distrust was justified. Narrow
mindedness and petty jealousy prevail everywhere alike.

I decide to help myself to this book, which I should never get by
asking. This is the half-holiday. The science master will not put
in an appearance today; and the key of my room is practically the
same as his. I go, with eyes and ears on the alert. My key does
not quite fit; it sticks a little, then goes in; and an extra
effort makes it turn in the lock. The door opens. I inspect the
cupboard and find that it does contain an algebra book, one of the
big, fat books which men used to write in those days, a book nearly
half a foot thick. My legs give way beneath me. You poor specimen
of a housebreaker, suppose you were caught at it! However, all goes
well. Quick, let's lock the door again and go back to our own
quarters with the pilfered volume.

And now we are together, O mysterious tome, whose Arab name
breathes a strange mustiness of occult lore and claims kindred with
the sciences of almagest and alchemy. What will you show me? Let
us turn the leaves at random. Before fixing one's eyes on a
definite point in the landscape, it is well to take a summary view
of the whole. Page follows swiftly upon page, telling me nothing.
A chapter catches my attention in the middle of the volume; it is
headed, Newton's Binomial Theorem.

The title allures me. What can a binomial theorem be, especially
one whose author is Newton, the great English mathematician who
weighed the worlds? What has the mechanism of the sky to do with
this? Let us read and seek for enlightenment. With my elbows on
the table and my thumbs behind my ears, I concentrate all my

I am seized with astonishment, for I understand! There are a
certain number of letters, general symbols which are grouped in all
manner of ways, taking their places here, there and elsewhere by
turns; there are, as the text tells me, arrangements, permutations
and combinations. Pen in hand, I arrange, permute and combine. It
is a very diverting exercise, upon my word, a game in which the
test of the written result confirms the anticipations of logic and
supplements the shortcomings of one's thinking apparatus.

'It will be plain sailing,' said I to myself, 'if algebra is no
more difficult than this.'

I was to recover from the illusion later, when the binomial
theorem, that light, crisp biscuit, was followed by heavier and
less digestible fare. But, for the moment, I had no foretaste of
the future difficulties, of the pitfall in which one becomes more
and more entangled, the longer one persists in struggling. What a
delightful afternoon that was, before my grate, amid my
permutations and combinations! By the evening, I had nearly
mastered my subject. When the bell rang, at seven, to summon us to
the common meal at the principal's table, I went downstairs puffed
up with the joys of the newly initiated neophyte. I was escorted
on my way by a, b and c, intertwined in cunning garlands.

Next day, my pupil is there. Blackboard and chalk, everything is
ready. Not quite so ready is the master. I bravely broach my
binomial theorem. My hearer becomes interested in the combinations
of letters. Not for a moment does he suspect that I am putting the
cart before the horse and beginning where we ought to have
finished. I relieve the dryness of my explanations with a few
little problems, so many halts at which the mind takes breath
awhile and gathers strength for fresh flights.

We try together. Discreetly, so as to leave him the merit of the
discovery, I shed a little light on the path. The solution is
found. My pupil triumphs; so do I, but silently, in my inner
consciousness, which says:

'You understand, because you succeed in making another understand.'

The hour passed quickly and very pleasantly for both of us. My
young man was contented when he left me; and I no less so, for I
perceived a new and original way of learning things.

The ingenious and easy arrangement of the binomial gave me time to
tackle my algebra book from the proper commencement. In three or
four days, I had rubbed up my weapons. There was nothing to be
said about addition and subtraction: they were so simple as to
force themselves upon one at first sight. Multiplication spoilt
things. There was a certain rule of signs which declared that
minus multiplied by minus made plus. How I toiled over that
wretched paradox! It would seem that the book did not explain this
subject clearly, or rather employed too abstract a method. I read,
reread and meditated in vain: the obscure text retained all its
obscurity. That is the drawback of books in general: they tell you
what is printed in them and nothing more. If you fail to
understand, they never advise you, never suggest an attempt along
another road which might lead you to the light. The merest word
would sometimes be enough to put you on the right track; and that
word the books, hidebound in a regulation phraseology, never give

How greatly preferable is the oral lesson! It goes forward, goes
back, starts afresh, walks around the obstacle and varies the
methods of attack until, at long last, light is shed upon the
darkness. This incomparable beacon of the master's word was what I
lacked; and I went under, without hope of succor, in that
treacherous pool of the rule of signs.

My pupil was bound to suffer the effects. After an attempt at an
explanation in which I made the most of the few gleams that reached
me I asked him:

'Do you understand? '

It was a futile question, but useful for gaining time. Myself not
understanding, I was convinced beforehand that he did not
understand either.

'No,' he replied, accusing himself, perhaps, in his simple mind, of
possessing a brain incapable of taking in those transcendental

'Let us try another method.'

And I start again this way and that way and yet another way. My
pupil's eyes serve as my thermometer and tell me of the progress of
my efforts. A blink of satisfaction announces my success. I have
struck home, I have found the joint in the armor. The product of
minus multiplied by minus delivers its mysteries to us.

And thus we continued our studies: he, the passive receiver, taking
in the ideas acquired without effort; I, the fierce pioneer,
blasting my rock, the book, with the aid of much sitting up at
night, to extract the diamond, truth. Another and no less arduous
task fell to my share: I had to cut and polish the recondite gem,
to strip it of its ruggedness and present it to my companion's
intelligence under a less forbidding aspect. This diamond cutter's
work, which admitted a little light into the precious stone, was
the favorite occupation of my leisure; and I owe a great deal to

The ultimate result was that my pupil passed his examination. As
for the book borrowed by stealth, I restored it to the shelves and
replaced it by another, which, this time, belonged to me.

At my normal school, I had learnt a little elementary geometry
under a master. From the first few lessons onwards, I rather
enjoyed the subject. I divined in it a guide for one's reasoning
faculties through the thickets of the imagination; I caught a
glimpse of a search after truth that did not involve too much
stumbling on the way, because each step forward rests solidly upon
the step already taken; I suspected geometry to be what it
preeminently is: a school of intellectual fencing.

The truth demonstrated and its application matter little to me;
what rouses my enthusiasm is the process that sets the truth before
us. We start from a brilliantly lighted spot and gradually get
deeper and deeper in the darkness, which, in its turn, becomes
self-illuminated by kindling new lights for a higher ascent. This
progressive march of the known toward the unknown, this
conscientious lantern lighting what follows by the rays of what
comes before: that was my real business.

Geometry was to teach me the logical progression of thought; it was
to tell me how the difficulties are broken up into sections which,
elucidated consecutively, together form a lever capable of moving
the block that resists any direct efforts; lastly, it showed me how
order is engendered, order, the base of clarity. If it has ever
fallen to my lot to write a page or two which the reader has run
over without excessive fatigue, I owe it, in great part, to
geometry, that wonderful teacher of the art of directing one's
thought. True, it does not bestow imagination, a delicate flower
blossoming none knows how and unable to thrive on every soil; but
it arranges what is confused, thins out the dense, calms the
tumultuous, filters the muddy and gives lucidity, a superior
product to all the tropes of rhetoric.

Yes, as a toiler with the pen, I owe much to it. Wherefore my
thoughts readily turn back to those bright hours of my novitiate,
when, retiring to a corner of the garden in recreation time, with a
bit of paper on my knees and a stump of pencil in my fingers, I
used to practice deducing this or that property correctly from an
assemblage of straight lines. The others amused themselves all
around me; I found my delight in the frustum of a pyramid. Perhaps
I should have done better to strengthen the muscles of my thighs by
jumping and leaping, to increase the suppleness of my loins with
gymnastic contortions. I have known some contortionists who have
prospered beyond the thinker.

See me then entering the lists as an instructor of youth, fairly
well acquainted with the elements of geometry. In case of need, I
could handle the land surveyor's stake and chain. There my views
ended. To cube the trunk of a tree, to gauge a cask, to measure
the distance of an inaccessible point appeared to me the highest
pitch to which geometrical knowledge could hope to soar. Were
there loftier flights? I did not even suspect it, when an
unexpected glimpse showed me the puny dimensions of the little
corner which I had cleared in the measureless domain.

At that time, the college in which, two years before, I had made my
first appearance as a teacher, had just halved the size of its
classes and largely increased its staff. The newcomers all lived
in the building, like myself, and we had our meals in common at the
principal's table. We formed a hive where, in our leisure time,
some of us, in our respective cells, worked up the honey of algebra
and geometry, history and physics, Greek and Latin most of all,
sometimes with a view to the class above, sometimes and oftener
with a view to acquiring a degree. The university titles lacked
variety. All my colleagues were bachelors of letters, but nothing
more. They must, if possible, arm themselves a little better to
make their way in the world. We all worked hard and steadily. I
was the youngest of the industrious community and no less eager
than the rest to increase my modest equipment.

Visits between the different rooms were frequent. We would come to
consult one another about a difficulty, or simply to pass the time
of day. I had as a neighbor, in the next cell to mine, a retired
quartermaster who, weary of barrack life, had taken refuge in
education. When in charge of the books of his company he had
become more or less familiar with figures; and it became his
ambition to take a mathematical degree. His cerebrum appears to
have hardened while he was with his regiment. According to my dear
colleagues, those amiable retailers of the misfortunes of others,
he had already twice been plucked. Stubbornly, he returned to his
books and exercises, refusing to be daunted by two reverses.

It was not that he was allured by the beauties of mathematics, far
from it; but the step to which he aspired favored his plans. He
hoped to have his own boarders and dispense butter and vegetables
to lucrative purpose. The lover of study for its own sake and the
persistent trapper hunting a diploma as he would something to put
in his mouth were not made to understand or to see much of each
other. Chance, however, brought us together.

I had often surprised our friend sitting in the evening, by the
light of a candle, with his elbows on the table and his head
between his hands, meditating at great length in front of a big
exercise book crammed with cabalistic signs. From time to time,
when an idea came to him, he would take his pen and hastily put
down a line of writing wherein letters, large and small, were
grouped without any grammatical sense. The letters x and y often
recurred, intermingled with figures. Every row ended with the sign
of equality and a nought. Next came more reflection, with closed
eyes, and a fresh row of letters arranged in a different order and
likewise followed by a nought. Page after page was filled in this
queer fashion, each line winding up with 0.

'What are you doing with all those rows of figures amounting to
zero? ' I asked him one day.

The mathematician gave me a leery look, picked up in barracks. A
sarcastic droop in the corner of his eye showed how he pitied my
ignorance. My colleague of the many noughts did not, however, take
an unfair advantage of his superiority. He told me that he was
working at analytical geometry.

The phrase had a strange effect upon me. I ruminated silently to
this purpose: there was a higher geometry, which you learnt more
particularly with combinations of letters in which x and y played a
prominent part. When my next-door neighbor reflected so long,
clutching his forehead between his hands, he was trying to discover
the hidden meaning of his own hieroglyphics; he saw the ghostly
translation of his sums dancing in space. What did he perceive?
How would the alphabetical signs, arranged first in one and then in
another manner, give an image of the actual things, an image
visible to the eyes of the mind alone? It beat me.

'I shall have to learn analytical geometry some day,' I said.
'Will you help me? '

'I'm quite willing,' he replied, with a smile in which I read his
lack of confidence in my determination.

No matter; we struck a bargain that same evening. We would
together break up the stubble of algebra and analytical geometry,
the foundation of the mathematical degree; we would make common
stock: he would bring long hours of calculation, I my youthful
ardor. We would begin as soon as I had finished with my arts
degree, which was my main preoccupation for the moment.

In those far off days it was the rule to make a little serious
literary study take precedence of science. You were expected to be
familiar with the great minds of antiquity, to converse with Horace
and Virgil, Theocritus and Plato, before touching the poisons of
chemistry or the levers of mechanics. The niceties of thought
could only be the gainers by these preparations. Life's
exigencies, ever harsher as progress afflicts us with its
increasing needs, have changed all that. A fig for correct
language! Business before all!

This modern hurry would have suited my impatience. I confess that
I fumed against the regulation which forced Latin and Greek upon me
before allowing me to open up relations with the sine and cosine.
Today, wiser, ripened by age and experience, I am of a different
opinion. I very much regret that my modest literary studies were
not more carefully conducted and further prolonged. To fill up
this enormous blank a little, I respectfully returned, somewhat
late in life, to those good old books which are usually sold
second-hand with their leaves hardly cut. Venerable pages,
annotated in pencil during the long evenings of my youth, I have
found you again and you are more than ever my friends. You have


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