1881.] Poisons of certain Indian Venomous Snakes. 343 



ful to allow, of the accelerating action of the poison being perceived. 

 But this quickening, however produced, is merely temporary, and is 

 followed by retardation. The simplest form in which to see the effect 

 of cobra poisoning on respiration is afforded by the common ' fowl. 

 The stethometric chart, marked No. 1, gives in a concise manner the 

 effects of cobra poisoning when the action is very gradual. 



The main points to be noticed are the slight quickening first per- 

 ceived, and the increase of the excursus. These are followed by 

 rapidly increasing retardation with a certain amount of lessening of 

 the excursus, though the excursus is less affected than the frequency. 

 It is also to be noticed that inspiration becomes sudden and abrupt, 

 and is immediately followed by an expiration equally sudden. The 

 movement that remains is, therefore, peculiarly unfavourable for 

 respiration. In the end the respiratory movement is entirely abolished, 

 and after a pause the convulsions of asphyxia terminate life. Chart 

 No. 2 presents some contrasts of interest. It gives nearly the whole 

 course of the respiratory movements of a fowl from the injection of 

 the poison till death, in a case in which a large amount of cobra 

 poison was given, causing death very rapidly. From it will be seen 

 how very much more pronounced the acceleration is when a large 

 quantity of poison is given, and that when the stage of acceleration is 

 passed the excursus is lessened quite as rapidly as the frequency. The 

 respirations before the administration of the poison bear to the respira- 

 tions at their greatest degree of acceleration in the tracing TV a ratio 

 of 4 to 7. Chart No. 3 is a series of tracings from a large pariah dog, 

 the acceleration followed by retardation, and the accompanying diminu- 

 tion of excursus are well shown, but the chief points of interest are 

 in the tracings of the occurrence of convulsions ; they begin by 

 regular contractions of the inspiratory muscles, in the period of their 

 greatest violence they lose all respiratory character, and then gradually 

 fade away in gentler and gentler attempts at inspiration. The cat is 

 an animal that shows a peculiar power of resisting cobra poison, pre- 

 senting a marked contrast to the dog. Chart No. 4 is from a cat in 

 whom this resisting power was well shown. After the retardation of 

 respiration is accomplished, it will be noticed that an occasional deep 

 respiration occurred; it is as if the animal, aware of its lessening 

 breathing power, made conscious efforts to assist respiration. A 

 similar feature appears to have been frequently noticed in the human 

 subject under like circumstances. The series of tracings in Chart 

 No. 5 shows graphically the instantly destructive character of cobra 

 poison on the respiratory function. They were taken from a dog on 

 whom the following observations were made. 



Experiment V. 



A powerful pariah dog had 1 cub. centim. of fresh cobra poison 



