《fabre, poet of science》

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fabre, poet of science- 第19部分


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work demands; what perseverance Fabre has required painfully to extract one

grain of gold; to glean and unite the definite factors; the positive

documents; which served as foundations for each of his essays; lucid;

limpid; and captivating as the most delightful of fairy…tales。 We are

charmed; fascinated; and astonished; we see nothing of the groping advance;

the checks; and all the toil and the patience demanded。 We do not suspect

the long waiting; the hesitation; the desperate length of the inquiries。

For example; to establish the curious relations which exist between the

wasps and the Volucellae; what long and repeated experiments were needful!

His notebooks; in which he records; from day to day; all that he sees; are

evidence of this。 What watches in the alley of lilacs; year after year; to

decipher the mechanism and the mode of construction of the hunting…net of

the Epe?ra! Some of these histories; like that of the hyper…metamorphosis

of the Melo?; were only completed as the result of twenty…five years of

assiduous inquiry; while forty years were required to complete that of the

Scarabaeus sacer; for his observation of it was always partial; it is

almost always impossible to divine what one cannot see from the little that

one does see; and as a rule one must return to the same point over and over

again in order to fill up lacunae。



The majority of the insects which Fabre has studied are solitary; and are

only to be encountered singly; scattered over wide areas of country。 Some

live only in determined spots; and not elsewhere; such as the famous

Cerceris; or the yellow…winged Sphex; of which no trace is to be found

beyond the limits of the Carpentras countryside。



The proper season must be watched for; one must be ready at any moment to

profit by a lucky chance; and resign oneself to interminable watches at the

bottom of a ravine; or keep on the alert for hours under a fiery sun。 Often

the chance goes by; or the trail followed proves false; but the season is

over; and one must wait for the return of another spring。 The trade of

observer in many cases resembles the exhausting labours of the Sisyphus

beetle; painfully pushing his pellet up a rough and stony path; so that the

team halts and staggers at every moment; the load spills over and rolls

away; and all has to be commenced over again。



We can now cast back; in order to consider at leisure the immortal study

which marked the beginning of his fame; with the greater interest and

profit in that Fabre has been able; during his retirement; to generalize

and extend his discovery。 (7/35。)



Let us first of all note how the observation which Dufour had made of the

nest of the Cerceris was transformed in his hands; and what developments he

was able to evolve therefrom。



Since they have been definitely established by Fabre these curious facts

have been well…known。 They form perhaps the greatest prodigy presented by

entomology; that science so full of marvels。



These wasps nourish themselves only on the nectar of flowers; but their

larvae; which they will never behold; must have fresh and succulent flesh

still palpitating with life。



The insect digs a tunnel in the soil; in which she places her eggs; and

having provisioned the cell with selected gamecricket; spider;

caterpillar; or beetleshe finally closes the entrance; which she does not

again cross。



Like nearly all insects; the young wasp is born in the larval state; and

from the moment of its hatching to the end of its growththat is to say;

for a period of many daysthe grub enclosed in its cell can look for no

help from without。



Here then is a fascinating problem: either the victims deposited by the

mother are dead; and desiccation or putrefaction attacks them promptly; or

else they are living; as indeed the larvae require; but then 〃what will

become of this fragile creature; which a mere nothing will destroy; shut in

the narrow chamber of the burrow among vigorous beetles; for weeks on end

working their long spurred legs; or at grips with a monstrous caterpillar

making play with its flanks and mandibles; rolling and unrolling its

tortuous folds?〃



Such is the thrilling mystery of which Fabre discovered the key。



With inconceivable ingenuity; the victim is seized and thrown to the

ground; and the wasp plunges her sting; not at random into the body; which

would involve the risk of death; but at determined points; exactly into the

seat of those invisible nervous ganglions whose mechanism commands the

various movements of the creature。



Immediately after these subtle wounds the prey is paralysed throughout its

body; its members appear to be disarticulated; 〃as though all the springs

were broken〃; the true corpse is not more motionless。



But the wound is not mortal; not only does the insect continue to live; but

it has acquired the strange prerogative of being able to live for a very

long period without taking any nourishment; thanks precisely to the

condition of immobility; in some sort vegetative; which paralysis confers

upon it。



When the hour strikes the hungry larva will find its favourite meat served

to its liking; and it will attack this defenceless prey with all the

circumspection of a refined eater; 〃with an exquisitely delicate art;

nibbling the viscera of its victim little by little; with an infallible

method; the less essential parts first of all; and only in the last

instance those which are necessary to life。 Here then is an

incomprehensible spectacle; the spectacle of an animal which; eaten alive;

mouthful by mouthful; during nearly a fortnight; is hollowed out; grows

less and less; and finally collapses;〃 while retaining to the end its

succulence and its freshness。



The fact is that the mother has taken care to deposit her egg 〃at a point

always the same〃 in the region which her sting has rendered insensible; so

that the first mouthfuls are only feebly resented。 But as the enemy goes

deeper and deeper 〃it sometimes happens that the cricket; bitten to the

quick; attempts to retaliate; but it only succeeds in opening and closing

the pincers of its mandibles on the empty air; or in uselessly waving its

antennae。〃 Vain efforts: 〃for now the voracious beast has bitten deep into

the spot; and can with impunity ransack the entrails。〃 What a slow and

horrible agony for the paralysed victim; should some glimmer of

consciousness still linger in its puny brain! What a terrible nightmare for

the little field…cricket; suddenly plunged into the den of the Sphex; so

far from the sunlit tuft of thyme which sheltered its retreat!



To paralyse without killing; 〃to deliver the prey to the larvae inert but

living〃: that is the end to be attained; only the method varies according

to the species of the hunter and the structure of the prey; thus the

Cerceris; which attacks the coleoptera; and the Scolia; which preys upon

the larvae of the rose…beetle; sting them only once and in a single place;

because there is concentrated the mass of the motor ganglions。



The Pompilus; which selects a spider for its victim; no less than the

redoubtable Tarantula; knows that its quarry 〃has two nervous centres which

animate respectively the movements of the limbs and those of the terrible

fangs; hence the two stabs of the sting。〃 (7/36。)



The Sphex plunges her dagger three times into the breast of the cricket;

because she knows; by an intuition that we cannot comprehend; that the

locomotor innervation of the cricket is actuated by three nervous centres;

which lie wide apart。 (7/37。)



Finally; the Ammophila; 〃the highest manifestation of the logic of

instinct; whose profound knowledge leaves us confounded; stabs the

caterpillar in nine places; because the body of the victim with which it

feeds its larvae is a series of rings; set end to end; each of which

possesses its little independent nervous centre。〃 (7/38。)



This is not all; the genius of the Sphex is not yet at the end of its

foresight。 You have doubtless heard of the comatose state into which the

wounded fall when; after a fracture of the skull; the brain is compressed

by a violent haemorrhage or a bony splinter。 The physiologists imitate this

process of nature when they wish; for example; to obtain; in animals under

experiment; a state of complete immobility。 But did the first surgeon who

thought of trepanning the skull in order to exert on the brain; by means of

a sponge; a certain degree of compression; ever imagine that an analogous

procedure had long been employed in the insect world; and that these clumsy

methods were merely child's play beside the astonishing feats of the

Unconscious?



For the stab in the thoracic ganglions; however efficacious; is often

insufficient。 Although the six limbs are paralysed; although the victim

cannot move; its mandibles; 〃pointed; sharp; serrated; which close like a

pair of scissors; still remain a menace to the tyrant; they might at least;

by gripping the surrounding grasses; oppose a more or less effectual

resistance to the process of carrying off。〃 So the preceding manoeuvres are

consummated by a kind of garrotting; that is; the insect 〃takes care to

compress the brain of its victim; but so as to avoid wounding it; producing

only a stupor; a simple torpor; a passing lethargy。〃 Is not the ingenious

observer justified in concluding that 〃this is alarmingly scientific〃?



Between the dry statements of Dufour; which served Fabre as his original

theme; and the unaccustomed wealth of this vast physiological poetry; what

a distance has been covered!



How far have we outstripped this barren matter; these shapeless sketches!

Dufour; another solitary; who retired to his province; in the depth of the

Landes; was above all a descriptive anatomist; and he limited himself to an

inventory of the nest of a Cerceris。



For him the Buprestes were dead; and their state of preservation was

ex
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