OF SERPENTS. IO9 



fa6ls afforded by chemical experiments, they admit 

 of further llluftration from fcrpents themfelves. The 

 heart of ferpents, and all other cold blooded animals, 

 has but one cavity, and the blood performs but one 

 circuit round the body, fo that a fmall portion only 

 pafles through the lungs: hence little of their blood 

 is expofed to the aftion of the atmofphere, it is there- 

 fore but little loaded with oxygen, it is not of i'o 

 high a colour, and the heat of their bodies is lefs. 



These fundamental truths have already given a 

 new appearance to the theory and pradice of medi- 

 cine, and they now lead me to conjecture that the 

 poifon of ferpents a6i:s upon the blood, by attracting 

 the oxygen, which it receives from the atmofphere in 

 its paifage through the lungs, and upon which its 

 vitality depends. 



In fupport of this opinion, I would adduce the 

 following arguments : 



1 . Man, and other warm blooded animals, expofed 

 to an atmofphere deprived of oxygen, quickly expire. 

 The poifon of a ferpcnt when introduced into the • 

 blood, alfo caufes death, but carried into circulation 

 by a wound, and in very fmall quantity, its operation 

 is comparatively How and gradual, 



2. The appearances on difTection in both cafes, 

 are very limilar. The blood becomes of a darker hue, 

 and coagulates about the heart and larger veifels i 

 the irritability of tlie fibres are nearlv to the Oime dt- 

 grec deflroyed, and the body has a krong tendcncv, in 

 both inftances, to putrefcency. 



3. Doctor Mead mixed the venom of the viper, 

 and healthy blood together out of the body, and he did 

 not perceive that it produced any change in its ap- 

 pearance : this arofe from his mixing a fmail quantity of 



