Covers of metallic gauze resting on earthenware saucers full of sand, a few carboys and flower-pots or sweetmeat jars closed with a square of glass; these serve as observation or experimental cages in which the progress and the actions of "these tiny living machines" can be examined.
Fabre has revealed himself as a psychologist without rival, of a consummate skill in the difficult and delicate art of experimentation; the art of making the insect speak, of putting questions to it, of forcing it to betray its secrets; for experiment is "the only method which can throw any light upon the nature of instincts."
His resources being slender and his mind inventive, he has ingeniously supplemented the poverty of his equipment, and has discovered less costly and less complex means of conducting his experiments; knowing the secret of extracting the sublimest truth from clumsy combinations of "trivial, peasant-made articles."
He has succeeded, in his rustic laboratory, in applying the rigorous rules of investigation and experimentation established by the great biologists. He has therefore been able to establish his beautiful observations in a manner so indisputable that those who come after him and are tempted to study the same things can but arrive at the same results, and derive inspiration from his researches.
To note with care all the details of a phenomenon is the first essential, so that others may afterwards refer to them and profit by them; the difficult thing is to interpret them, to discover the circumstances, the whys and wherefores, the consequences, and the connecting links.
But a single fact observed by chance at the wayside, and which would not even attract the attention of another, will be instantly luminous to this searching understanding, it will suggest questions unforeseen, and will evoke, by anticipation, preconceived ideas and sudden flashes of intuition, which will necessitate the test of experiment.
Why, for example, does the Philanthus, that slender wasp, which captures the honey-bee upon the blossoms in order to feed her larvae; why, before she carries her prey to her offspring, does she "outrage the dying insect," by squeezing its crop in order to empty it of honey, in which she appears to delight, and does indeed actually delight?
"The bandit greedily takes in her mouth the extended and sugared tongue of the dead insect; then once more she presses the neck and the thorax, and once more applies the pressure of her abdomen to the honey-sac of the bee. The honey oozes forth and is instantly licked up. Thus the bee is gradually compelled to disgorge the contents of the crop. This atrocious meal lasts often half an hour and longer, until the last trace of honey has disappeared."
The detailed answer is obtained by experiment, which perfectly explains this "odious feast," the excuse for which is simply maternity. The Philanthus knows, instinctively, without having learned it, that honey, which is her ordinary fare, is, by a very singular "inversion," a mortal poison to her larvae. [(7/31.)]
As an accomplished physiologist, Fabre conducts all kinds of experiments. Behind the wires of his cages, he provokes the moving spectacle of the scorpion at grip with the whole entomological fauna, in order to test the effects of its terrible venom upon various species; and thus he discovers the strange immunity of larvae; the virus, "the reagent of a transcendent chemistry, distinguishes the flesh of the larva from that of the adult; it is harmless to the former, but mortal to the latter"; a fresh proof that "metamorphosis modifies the substance of the organism to the point of changing its most intimate properties." [(7/32.)]