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CHAPTER? VE: 
PHYSIOLOGY OF POISONING (continued). 
ACTION OF VENOMS ON THE BLOOD. 
ON making an autopsy of an animal which has succumbed to 
intoxication by snake-venom, we find that the blood in the heart 
and large vessels is sometimes coagulated into a mass, sometimes 
entirely fluid, and that, in certain cases, it is as black as prune- 
juice, while in others it is of a fine transparent red colour. 
These differences in the effects of venom upon the blood are 
due to the fact that the various venoms contain in variable pro- 
portions, besides the neurotoxic substance which represents the 
true venomous {orin, other substances which act, some upon the 
plasmasia or fibrin-ferment, or upon the fibrin, others upon the 
red corpuscles, others on the leucocytes, and others again on the 
endothelium of the blood-vessels. 
A.— EFFECTS OF VENOM ON THE COAGULATION OF THE BLoob. 
It was observed long ago by Fontana! that after viper-bites 
the blood remains fluid, and Brainard’ on the contrary, pointed 
out that, in the case of animals that succumb very rapidly after 
having been bitten by a Crotalus, the blood was always found 
coagulated into a mass, while, when a certain interval of time 
had elapsed since the bite, it remained fluid. Weir Mitchell® 
' Fontana, “On Poisons,” translated by J. Skinner: London, 1787. 
? Smithsonian Reports, 1854. 
> Smithsonian Contributions to Knowledge, 1860. 
