64 Proceedings 
the first segments of the body; when walking the head is pro- 
truded a little. 
Feeling certain that this was an exceedingly venomous cater- 
pillar I determined tosting myself with it and observe the results. 
At 11 a.m. I applied the back of the caterpillar to the back 
of my left hand with sufficient pressure to feel the pricking of 
the spines. In ten minutes I had violent pain in the hand, and 
the place of contact had swollen up into a white lump, sur- 
rounded by a dark red inflamed patch. A few minutes later, 
violent pain set in under the armpit. I applied strong ammonia 
to the hand, but the only result was to remove the white lump, 
the pain and the red patch remaining the same. I next tried 
vinegar, but with no effect. At 11.30 a red rash appeared on 
the inside of the elbow, and this gradually extended up to the 
shoulder along the biceps, and down the arm to the place of 
injection on the hand. The rash was slight excepting at the 
elbow. At 12 o'clock the pain was still violent and burning, but 
not so bad as it had been. 
I have been informed by Brazilians that the mere crawling 
of the caterpillars over the skin causes this rash and burning 
pain; but such is not my experience, for I have allowed several 
species to crawl over me without any ill effects at all. It appears 
that pressure must be brought directly on to the ends of the 
spines to make them eject the poison, the caterpillar being mere- 
ly passive and incapable of ejecting the fluid itself. 
Soon after 12 o’clock I noticed a sensible weakness in the 
hand and arm, but was not able to say for certain whether it 
was the effect of the extreme pain or a distinct effect of the 
poison; but from later symptoms I lean to the latter opinion. 
At 12.15 the rash down the arm began to disappear, and 
the pain under the arm was sensibly diminished though still 
considerable. The affected area on the hand began to perspire 
profusely though the rest of the body had no visible perspira- 
tion. The pain in the injected spot was as violent as ever, burn- 
ing horribly. The effect was more like a scald than anything 
else I can compare it with. The pain increasing, at 12.30 I 
applied a wet bandage to the hand. At 1 p.m. the pain in the 
armpit had nearly ceased, and the rash on the arm had dis- 
