VOL. LXX.] PHILOSOPHICAL TilANSACTIONS. 663 



torpor continued in some for many hours; but then again others continued as 

 lively as before. 



After all these experiments it may be safely asserted, that the American 

 poison is entirely innoxious to cold-blooded animals, as is the poison of the 

 viper; in which respect these 2 poisons have a great analogy, though the one 

 be no more than an animal gum, as I have shown elsewhere, and the other 

 a mere vegetable juice. 



It remained to examine the action of this poison on living animals; and also 

 which are the particular parts of animals that are affected by it when it proves 

 fatal. Every thing tended to make us think, that it excites one of those disorders 

 which modern physicians call nervous. The symptoms are precisely and deci- 

 sively the symptoms of those diseases. Convulsions, faintness, a total loss of 

 strength and motion, a diminution or entire want of sensation, are the ordinary 

 symptoms of the poison, in animals. It has often been observed, that very 

 lively animals become in a moment senseless and motionless, and seem at the 

 point of death. I have generally observed a symptom which seems to be a real 

 demonstration that the disorder produced by this poison is purely nervous. If 

 the animals do not die in a few minutes, they perfectly recover again, though 

 they have been thrown into a state of lethargy often for hours, and have not 

 given any certain and evident signs of life. Now this is the very case with the 

 disorders which are called nervous. They frequently come on at once; they 

 sometimes excite convulsive motions, and sometimes they deprive the patient of 

 all strength ; but as soon as the effects of the disorder cease, the patient becomes 

 perfectly well, and is hardly sensible that he has been ill. Notwithstanding all 

 this, these signs could not impose on me after my experiments on the poison of 

 the viper: for the disorder produced by that poison has also some symptoms of 

 the nervous disorders, and it appears that the nerves are chiefly affected, though 

 experiments have determined the contrary ; therefore we ought here also to have 

 recourse to experiments, and not suffer ourselves to be seduced by an unfounded 

 theory, and by specious reasonings. 



To proceed methodically in this important question, I thought it would be 

 proper to begin by examining whether the American poison produces any sensible 

 alteration in the blood drawn from the veins of animals, when it is mixed with 

 it, I cut off the head of a pigeon, and received its warm blood into 2 warm 

 conical glasses, to the amount of about 80 drops into each. Into the 1 glass I 

 put 4 drops of water, and into the other 4 drops of the poison, dissolved in 

 water as usual ; the quantity of poison in these 4 drops scarcely amounting to 

 1 gr. in weight when dry. I stirred round equally the contents of the 2 glasses 

 for a few seconds, in order to mix the materials well together. In 2 minutes the 

 blood which was mixed with the pure water was coagulated; but the other blood 

 which was united with the American poison never coagulated, but became darker 



