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 Dahoia russellii can pass through the diges- 

 tive tract without serious disturbance. C. J. Martin found that feeding rats 

 with nearly loo 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 Viperidae may produce in 

 young mammalians inflammation of the mucous membrane of the stomach 

 or intestine. Thus, the venom of Lachesis provokes, when given in suffi- 

 cient dose, a violent inflammation of the gastric and intestinal mucous mem- 

 brane, and the animal dies of extensive haemorrhage 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 1 16 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 ^ 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.oooi gm. and above of the 

 bile of the same snake, but required 0.0003 gm. and above of rattlesnake 

 bile, or o.ooi gm. of the bile of puff adder. With grass-snake bile 0.00025 



J Fraser. The treatment of snake poisoning with antivenene derived from animals protected against 

 serpents' venom. Brit. Med. Tour, 1895, II, 416. _ /r. ■. tvt j t 



2 Fraser. The antivenomous properties of the bile of serpents and other animals. (Bnt. Med. J our, 

 1897, II, 125.) In connection with this experiment it may be stated that as early as 1870 b. 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 



