Truth is always veiled in a certain mystery. The good fortune that secured me the ravaged pupa taught me nothing concerning the tactics of the ravager. I have never seen the Chalcidid explore the contents of my appliances; my attention was engaged elsewhere and nothing is so difficult to see as a thing not yet suspected.
But, though direct observation be lacking, logic will tell us approximately what we want to know.
It is evident, to begin with, that the invasion cannot have been made through the sturdy amour of the pupae. This is too hard to be penetrated by the means at the pigmy's disposal. Naught but the delicate skin of the maggots lends itself to the introduction of the germs. An egg laying mother, therefore, appears, inspects the surface of the pool of sanies swarming with grubs, selects the one that suits her and perches on it; then, with the tip of her pointed abdomen, whence emerges, for an instant, a short probe kept hidden until then, she operates on the patient, perforating his paunch with a dexterous wound into which the germs are inserted.
Probably, a number of pricks are administered, as the presence of thirty parasites seems to demand.
Anyway, the maggot's skin is pierced at either one point or many;and this happens while the grub is swimming in the pools formed by the putrid flesh. Having said this, we are faced with a question of serious interest. To set it forth necessitates a digression which seems to have nothing to do with the subject in hand and is nevertheless connected with it in the closest fashion. Without certain preliminaries, the remainder would be unintelligible. So now for the preliminaries.
I was in those days busy with the poison of the Languedocian scorpion and its action upon insects. To direct the sting toward this or the other part of the victim and moreover to regulate its emission would be absolutely impossible and also very dangerous, as long as the scorpions were allowed to act as they pleased. Iwished to be able myself to choose the part to be wounded; Ilikewise wished to vary the dose of poison at will. How to set about it? The scorpion has no jarlike receptacle in which the venom is accumulated and stored, like that possessed, for instance, by the wasp and the bee. The last segment of the tail, gourd shaped and surmounted by the sting, contains only a powerful mass of muscles along which lie the delicate vessels that secrete the poison.
In default of a poison jar which I would have placed on one side and drawn upon at my convenience, I detach the last segment, forming the base of the sting. I obtain it from a dead and already withered scorpion. A watch glass serves as a basin. Here, I tear and crush the piece in a few drops of water and leave it to steep for four-and-twenty hours. The result is the liquid which Ipropose to use for the inoculation. If any poison remained in my animal's caudal gourd, there must be at least some traces of it in the infusion in the watch glass.
My hypodermic syringe is of the simplest. It consists of a little glass tube, tapering sharply at one end. By drawing in my breath, I fill it with the liquid to be tested; I expel the contents by blowing. Its point is almost as fine as a hair and enables me to regulate the dose to the degree which I want. A cubic millimeter is the usual charge. The injection has to be made at parts that are generally covered with horn. So as not to break the point of my fragile instrument, I prepare the way with a needle, with which I prick the victim at the spot required. I insert the tip of the loaded injector in the hole thus made and I blow. The thing is done in a moment, very neatly and in an orthodox fashion, favorable to delicate experiments. I am delighted with my modest apparatus.
I am equally delighted with the results. The scorpion himself, when wounding with his sting, in which the poison is not diluted as mine is in the watch glass, would not produce effects like those of my pricks. Here is something more brutal, producing more convulsion in the sufferer. The virus of my contriving excels the scorpion's.
The test is several times repeated, always with the same mixture, which, drying up by spontaneous evaporation, then made to serve again by the addition of a few drops of water, once more drained and once more moistened, does duty for an indefinite length of time. Instead of abating, the virulence increases. Moreover, the corpses of the insects operated upon undergo a curious change, unknown in my earlier observations. Then the suspicion comes to me that the actual poison of the scorpion does not enter into the matter at all. What I obtain with the end joint of the tail, with the gland at the base of the sting, I ought to obtain with any other part of the animal.
I crush in a few drops of water a joint of the tail taken from the front portion, far from the poison glands. After soaking it for twenty-four hours, I obtain a liquid whose effects are absolutely the same as those before, when I used the joint that bears the sting. I try again with the scorpion's claws, the contents of which consist solely of muscle. The results are just the same.
The whole of the animal's body, therefore, no matter which fragment be submitted to the steeping process, yields the virus that so greatly pricks my curiosity.
Every part of the Spanish fly [Cantharis or blistering beetle], inside and out, is saturated with the blistering element; but there is nothing like this in the scorpion, who localizes his venom in his caudal gland and has none of it elsewhere. The cause of the effects which I observe is therefore connected with general properties which I ought to find in any insect, even the most harmless.
