no ON THE POISON 



the venom with a large quantity of the blood : but if 

 two or three drops of venom be mixed with forty, or 

 fifty drops of blood, it immediately lofcs its vermilliofi 

 colour, becomes black, and incapable of coagulation. 



4. It is a very remarkable circumftance, that the 

 poifon of the ferpent has molt power over thofe ani- 

 mals, whofe biood is the warmeft, and the a6tion of 

 whofe heart is the mod lively : while on the contrary, 

 it is not a poifon to the ferpent itfelf, nor in general 

 to cold blooded animals. The reafon appears to be 

 this: cold blooded animals do not require a large 

 quantity of oxygen to preferve them in health; this 

 is evident from the conformation of their heart, and 

 refpiratory organs, as already mentioned. It does not 

 however follow, that no quantity of the venom would 

 deftroy them, for it is alfo evident from their polfelTing 

 refpiratory organs of any kind, that a certain quantity 

 of oxygen is abfolutely neceflary, and hence we know 

 that fome of them, fuch as frogs, may be killed bv 

 the venom, though it always produces its effects more 

 ilowly upon them, than upon animals with warm 

 blood. 



Having thus endeavoured toafcertain the method 

 in v.'liich the poifon operates, it may now be alked, 

 what fubliance can it be, that fo ftrongly attrafts the 

 oxygen of the blood? The venom is inodorous and 

 inlipid, contrary to the opinion of Doctor Mead, it is 

 neither fharp nor fiery, for it has fcarcejy any percep- 

 tible tafte ; it has the appearance, and fenlible pro- 

 perties of an animal mucus, but this mucus is evidently 

 a vehicle to fome very a6Hvc matter: on this fubject 

 it would not be difficult to conje£ture, but as in the 

 prefent flate of our knowledge, no conje6iure we 

 could offer could be eftabliflied upon any latisfaciory 

 grounds, we fljall leave this part of the fubjecf for 



future invcftigation. 



.SEC^ 



