POISON OF SOME INDIAN VENOMOUS SNAKES. 103 



Mean blood- 

 pressure. Pulse per 

 Time. millims. minute. 



milliras. Five beats more 

 raised it to 120. Height of 

 each pulse- wave about 15 

 millims. 



2.29 30 ... Tlie pulse has been getting 



smaller and smaller, and the 

 intervals longer and longer ; 

 it is now imperceptible. 



2.30 30 ... The pressure still seems at 30, 



notwithstanding the imper- 

 ceptibility of the pulse. 

 2.45 ... ... The heart was cut out. It still 



contracted when irritated. 



The injection of cobra-poison here caused a diminution of 

 the blood-pressure at first ; but a further injection again raised 

 it. In the latter part of the experiment there is not the 

 slightest trace of failure of the heart's action, but, on the 

 contrary, every evidence of powerful action. When the 

 respirations failed, the heart became slow from irritation of 

 the roots of the vagus by venous blood ; and the pulsations 

 were gradually weakened by the same condition. The fact that 

 the blood-pressure sank slowly and did not fall below 30, even 

 after the heart had almost entirely ceased, shows that the 

 arterioles were much contracted. 



Experiment LXXY. 



A cannula was placed in the carotid artery of a rabbit and 

 connected with a kymographion. 



The blood-pressure was 75 mm. of mercury. One cubic 

 centimetre of a 2-per-cent. solution of cobra-poison was injected 

 into the jugular vein. Almost immediately the animal began 

 to struggle, and the pressure rose to 95. It remained at this 

 for a minute and then fell. The float unfortunately stuck, and 

 the curve it should have described in falling v/as consequently 

 lost. On again getting the instrument to work, the pressure 



