CHAPTER IX. 
THE EFFECTS OF FERMENTS UPON SNAKE VENOM. 
The effects of certain proteolytic enzymes upon toxic constituents of various 
venoms have been studied by several investigators. The very early experi- 
ments of Weir Mitchell on the loss of the poisonous property of crotalus 
venom as administered by the alimentary canal indicate that the destruction 
of the toxicity of this venom while passing through the digestive tract of 
pigeons is due to the action of the proteolytic ferments. His elaborate work 
on this point is very interesting. Later, he, together with Reichert, states 
that by digestion in strong artificial gastric juice made from the pig’s stomach 
the toxic power of crotalus venom is completely destroyed. 
Fayrer states that the venom of Daboia russellii can pass through the diges- 
tive tract without serious disturbance. C. J. Martin found that feeding rats 
with nearly roo times minimal lethal doses (when injected) of the venom of 
Pseudechis porphyriacus does not cause any symptom during a whole week. 
The venom can not be recovered from the feces. Calmette, while confirming 
Martin’s experiment, mentions that the venom of Viperide may produce in 
young mammalians inflammation of the mucous membrane of the stomach 
or intestine. Thus, the venom of Lachesis provokes, when given in suff- 
cient dose, a violent inflammation of the gastric and intestinal mucous mem- 
brane, and the animal dies of extensive hemorrhage in the digestive tract 
even before any nervous symptom is manifest. 
Fraser ! observed almost no symptom in feeding a cat with cobra venom, 
starting with a subminimum lethal dose and increasing gradually to 80 mini- 
mal lethal doses in 116 days. In white rats similar tolerance was experienced, 
1.000 minimal lethal dose being administered with impunity. In both cases 
a very feeble antitoxic power developed in the serums of these animals. 
Fraser 2 attributes this innocuousness of venom when administered as food 
to the antivenomous property of the bile of these animals. He tested the bile 
of Naja haje, the puff adder, rattlesnake, and grass snake, against the venom 
of Naja haje and Naja tripudians. Naja haje venom 0.000245 per kilo 
body weight applied to rabbit was fatal. This venom in dose of 0.00025 
per kilo was made inert when mixed with o.coor gm. and above of the 
bile of the same snake, but required 0.0003 gm. and above of rattlesnake 
bile, or o.oor gm. of the bile of puff adder. With grass-snake bile 0.00025 

i NE eee 
1 Fraser. The treatment of snake poisoning with antivenene derived from animals protected against 
serpents’ venom. Brit. Med. Jour, 1895, II, 416. 
2Fraser. The antivenomous properties of the bile of serpents and other animals. (Brit. Med. Jour., 
1897, II, 125.) In connection with this experiment it may be stated that as early as 1870 S. B. 
Higgins (of South America) wrote Fayrer about the antivenomous property of the bile of cobra 
against some of the South American venoms, but the latter did not recognize this property. 
103 
