CHAPTER XXII. 



EFFECTS OF SNAKE VENOM ON MUCOUS, CONJUNCTIVAL, AND 

 SEROUS MEMBRANES AND THE ALIMENTARY TRACT. 



Weir Mitchell has shown that crotalus venom can be ingested by the pigeon, 

 one of the most susceptible animals to this venom, with impunity, and no 

 poisonous principle is recoverable from the excreta of the pigeon. Naturally 

 this may depend upon two possibilities: the non-absorption of the venom 

 through the buccal mucous membrane and the destructive action of the 

 gastric and intestinal ferments. 



Mitchell and Reichert applied venom directly to the gastric membrane 

 under laparotomy and found no visible changes produced by a few hours' 

 contact. This they ascribed to the non-absorption of the venom by unbroken 

 mucous membrane. Here they did not pay attention to the inactivating 

 action of hydrochloric acid — even in a very dilute concentration — upon 

 the hsemorrhagin of the venom; hence their conclusion regarding this particu- 

 lar phenomenon may require some modification. 



The recent investigation of Ishizaka on the production of active immunity 

 through oral administration of lachesis venom lends color to the occurrence 

 of the absorption of that venom from the intestinal canal. 1 



Lacerda, Calmette, and C. J. Martin state that the venoms of Lachesis 

 lanceolatus and Pseudechis may cause intense inflammation and haemorrhagic 

 changes in the alimentary tract when sufficient quantities of these venoms 

 are given by the mouth. If the dosage be sufficiently large death usually 

 follows their administration, with the usual venom-poisoning symptoms. 



With the venom of cobra alimentary administration gives somewhat dif- 

 ferent results from those obtained in the case of crotaline venoms. Brunton 

 and Fayrer observed that fatal effect is produced in animals when cobra 

 venom is given from the digestive tract by feeding. 



Fraser points out that absorption of cobra venom from the stomach is very 

 slight. In rats and cats nearly 1,000 times the subcutaneous lethal dose 

 was given without fatal effect. As a result of such administration of venom 

 the/serum of these animals was found to contain a certain amount of antitoxin. 



Calmette failed to confirm Fraser's experiments, as he always found the 

 venom to act fatally when given by the mouth in large dosage. 



Kanthack fully confirms Fraser's observations that immunity can be secured 

 by feeding the venom to animals. 



Briot and Massol have seen that cobra venom is more rapidly absorbed 

 from the rectum of animals than from the areolar tissue of the skin. The 



i The absorbtion of foreign proteins through the alimentary tract has been recently demonstrated by 

 Rosenau and Anderson by anaphylactic phenomena. 



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