66 INTRODUCTION 



mucous membrane surrounding the base of the 

 fangs, and is mixed with ordinary saliva, the mem- 

 branes of the mouth perhaps acting as lips, in which 

 case the term " spitting " would not be incorrect. The 

 spitting, which may take place three or four times 

 in succession, has been observed to be preceded by 

 some chewing movements of the jaws. If reaching 

 the eye, the poisonous fluid causes severe inflamma- 

 tion of the cornea and conjunctiva, but no more 

 serious results if washed away at once. 



Snake poisons is a subject which has always 

 attracted much attention, and which has made great 

 progress within the last quarter of a century, es- 

 pecially as regards the defensive reaction by which 

 the blood may be rendered proof against their effect 

 by processes similar to vaccination — antipoisonous 

 serotherapy. The studies to which we allude have 

 not only conduced to a method of treatment against 

 snake-bites, but have thrown a new light on the 

 great problem of immunity. They have shown that 

 the antitoxic serums do not act as chemical antidotes 

 in destroying the venom, but as physiological anti- 

 dotes ; that, in addition to the poison glands, snakes 

 possess other glands supplying their blood with 

 substances antagonistic to the poison, such as also 

 exist in various animals refractory to snake poison, 

 the hedgehog and the mungoose for instance. 

 Unfortunately, the specificity of the different snake 

 poisons is such that, even when the physiological 



