Very happy in my suffering, which sets me on a safe path, I continue my enquiry by arguing thus: the virus in the blood cannot be a living substance, one that takes part in the working of the organism; it is rather, like urea, a form of decay, an offthrow of the vital process, a waste product which is expelled as and when it forms. If this be the case, I ought to find it in the caterpillar’s droppings, which are made up of both the digestive and the urinary residues.
Let us describe the new experiment, which is no less positive than the last. I leave a few pinches of very dry droppings, such as are [[164]]found in abundance In the old nests, to soak for two days In sulphuric ether. The liquid, coloured as it is with the chlorophyll of the caterpillar’s food, turns a dirty green. Then I repeat precisely the process which I mentioned when I wanted to prove the innocuousness of the hairs deprived of their poisonous varnish. I refer to it a second time in order thoroughly to explain the method pursued and to save repetition in the various experiments undertaken.
The infusion is filtered, spontaneously evaporated and reduced to a few drops, with which I soak my stinger. This consists of a small piece of blotting-paper, folded in four to increase the thickness of the pad and to give it a greater power of absorption. An area of a square inch or less suffices; in some cases it is even too much. A novice in this kind of research-work, I was too lavish with the liniment; and in return for my generosity I had such a bad time that I make a point of warning any reader desirous of repeating the experiment upon his own person.
Fully soaked, the square of paper is applied to the fore-arm, on the inner surface, where the skin is more tender. A sheet of rubber [[165]]covers it and, being waterproof, guards against the loss of the poison. Finally, a linen bandage keeps the whole in place.
On the afternoon of the 4th of June 1897, a memorable date for me, I test, as I have just said, the etheric extract of the Processionary’s droppings. All night long, I feel a violent itching, a burning sensation and shooting pains. On the following day, after twenty hours of contact, I remove the dressing.
The venomous liquid, too lavishly employed in my fear of failure, has considerably overflowed the limits of the square of paper. The parts which it has touched and still more the portion covered by the pad are swollen and very red; moreover, in the latter case, the skin is ridged, wrinkled and mortified. It smarts a little and itches; and that is all.
On the following day, the swelling becomes more pronounced and goes deep into the muscles, which, when touched with the finger, throb like an inflamed cheek. The colour is a bright carmine and extends all round the spot which the paper covered. This is due to the escape of some of the liquid. There is a plentiful discharge of serum, oozing from the sore in tiny drops. The smarting and itching [[166]]increase and become so intense, especially during the night, that, to get a little sleep, I am driven to employ a palliative, vaseline with borax and a lint dressing.
In five days’ time, it has developed into a hideous ulcer, which looks more painful than it really is. The red, swollen flesh, quivering and denuded of its epidermis, provokes commiseration. The person who night and morning renews my dressing of lint and vaseline is almost sick at the sight.
“One would think,” she says, “that the dogs had been gnawing your arm. I do hope you won’t try any more of those horrible decoctions.”
I allow my sympathetic nurse to talk away and am already meditating further experiments, some of which will be equally painful. O sacred truth, what can rival thy power over us mortals! Thou turnest my petty torment into contentment; thou makest me rejoice in my flayed arm! What shall I gain by it all? I shall know why a wretched caterpillar sets us scratching ourselves. Nothing more; and that is enough for me.