654 PHILOSOPHICAL TRANSACTIONS. [aNNO 1780. 



and blacker than the former, which remained red as usual. Three hours after 

 it was still as fluid as at first, while in the other glass the serum appeared to be 

 already separated from the red part. I examined the blood of both glasses with a 

 microscope, both at that time and afterwards, and found that the red globules 

 still preserved their original figure, and that the'-e was no difference laetween 

 the 2 in this respect. 



I repeated this experiment many times with the same success; so that it is 

 evident, that the American poison does not sensibly alter the red globules of the 

 blood in the circumstance abovementioned. It is however worthy of observa- 

 tion, that this poison is so far from coagulating the blood, that it absolutely 

 prevents the coagulation which iiappens in the blood after it is drawn from 

 animals; yet it cannot be said to attenuate or dissolve the blood, since nothing 

 of that kind is observed when it is examined with a microscope, the red part 

 remaining figured as in its natural state, and nothing more subtle or more thin 

 being observable in that fluid. 



A circumstance perfectly similar I also observed to happen with the poison of 

 the viper; so that the effects or alterations caused by these 2 poisons in the 

 blood drawn from the vessels, appear to be perfectly similar, both of them hin- 

 dering the blood from coagulating, yet neither of them dissolving or altering 

 the globules of it: the only difference between them is, that the poison 

 of the viper tinges the blood much blacker than the American poison does. 

 The poison of the viper does not alter the globules of the blood even when it is 

 given to the living animal, and that the animal in consequence dies. I have 

 observed the same thing with respect to those animals which are killed by the 

 American poison; so that the 2 poisons agree in a wonderful manner in all these 

 cases. But as the poison of the viper produces in general a sensible alteration in the 

 mass of the blood of those animals that are bitten by it; I thought that the same 

 attention ought to be paid to the examination of the blood of those animals 

 which have died of the American poison. 



I have observed in general, that the muscles of animals killed by the American 

 poison were paler than before; the blood vessels near the heart appeared more 

 turgid than usual ; the blood a little darker coloured than ordinary, though not 

 much, nor coagulated ; the viscera of the abdomen not sensibly affected; the 

 heart and the auricles in the natural state, though the heart had sometimes its 

 external vessels more visible, and they appeared as if they were injected. But I 

 have observed a great alteration in one of the viscera, the most essential to life, 

 to wit, the lungs, which always appearcxi greatly affected. I iiave generally 

 found them spotted more or less; often with large and livid spots, and sometimes 

 they seemed to be quite putrified. This ettect on a viscus so essential to life 

 deserves the greatest attention: it appeared to me, that it was the greater the 

 longer the animal had lived after being poisoned. I have observed the lungs of 



