128 Messrs. T. L. Brunton and J. Fayrer on the [Jan. 22 f 



Mean blood-pressure. Pulse 

 Time. ruillims. per minute. 



more raised it to 120. Height of 

 each pulse-wave about 15 millims. 



2.29 30 . . The pulse has been getting smaller 



and smaller, and the intervals 

 longer and longer ; it is now im- 

 perceptible. 



2.30 30 . . The pressure still seems at 30, not- 



withstanding the imperceptibil- 

 lity 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 LXXV. 



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

 with a kymographion. 



The blood-pressure was 75 millims. of mercury. One cub. centim. 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 unfor- 

 tunately stuck, and the curve it should have described in falling was con- 

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

 found to be 25 ; and this continued, although the heart had ceased to beat 

 and the thorax was opened. On cutting across the aorta, the pressure fell 

 to zero, showing that it had not been due to any clot in the vessel. 



In this experiment the poison seems to have caused tetanic contraction 

 of the heart, and also of the arterioles. The permanence of the pressure 

 at 25, notwithstanding the stoppage of the heart's action, can only be 

 ascribed to contraction of the arterioles preventing the escape of blood 

 from the arterial into the venous system. 



Excretion of Snake-poison. 



We have made only one or two experiments, ourselves, on the excretion 

 of cobra-venom ; but, from the data affordeel by the experiments and ob- 

 servations of others, we consider that it is excreted by the kidneys and 

 mammary glands, and probably also by the salivary glands and mucous 



