POISON OF SOME INDIAN VENOMOUS SNAKES. 89 



Action of Cohra-poison on the Stomach and Intestines. 



One of the most noticeable symptoms of cobra-poisoning in 

 dogs is vomiting of a violent, repeated, and most distressing 

 kind ; and it is also present in cats and guinea-pigs, though to 

 a less degree. Its occurrence in guinea-pigs is somewhat extra- 

 ordinary, as these animals very rarely vomit, and, according 

 to Schiff, only do so after their vagi have been divided ; whereas 

 other animals which vomit under ordinary circumstances are 

 then unable to vomit at all. The nervous centre by which 

 the movements of vomiting are originated is closely connected 

 with the respiratory centre, and it may be set in action by 

 stimuli conveyed to it by the branches of the vagus distributed 

 to the stomach and other intestinal organs, and also through 

 the pharyngeal branches, either of the vagus or, possibly, of 

 the glosso-pharyngeal nerve. The brain can also excite it ; but 

 the vomiting it produces is not usually prolonged. The 

 vomiting which occurs in cobra-poisoning is, in all probability, 

 due, in part, to irritation of the gastric or abdominal branches 

 of the vagus — but not altogether ; for the attempts to vomit 

 continued in Experiment LXY after that nerve had been 

 divided in the neck ; and the failure to bring anything up is 

 to be attributed to the cardiac aperture of the stomach failing 

 to dilate at the proper time — a result which usually occurs 

 after section of the vagus. 



In Experiment XL IV there was intense congestion of the 

 mucous membrane of the stomach ; but this does not occur in 

 all cases. It could hardly be due to the division of the vagi 

 in this instance, as that operation is usually followed by paleness 

 of the membrane. The intestinal movements are quickened by 

 the poison, since there is purging, which cannot be due to 

 increased intestinal secretion, as the stools consist chiefly of 

 mucus. The movements continue for a considerable time after 

 death. 



Effect of Cohra-poison npon Respiration. 



The action of cobra-poison upon respiration is perhaps the 

 most important of those which it exerts upon the organism ; 

 for it is through this action that death is generally caused. 



