SNAKE-POISON AND ITS ACTION. 23 



and the paralysed veins ot the abdomen became 

 engorged once more with the whole, or nearly the 

 whole, of the blood-mass, leaving the rest of the body 

 ansemic as before. This interesting experiment also 

 shows how sti"ong a hold the snake-poison has on 

 the nerve-cells when they are. thoroughly under its 

 influence, and how independent this paralysing action 

 is of the blood, persisting, as it was in this case, after 

 all the poison had been washed out of the animal. 



The heart in vaso-motor paresis and paralysis is 

 weakened in the first instance by the direct action of 

 the poison on the medulla oblongata and the intra- 

 cardial ganglia. Its pulsations, at first retarded in 

 frequency, become accelerated soon after the intro- 

 duction of the poison, the pulse rate increasing rapidly 

 and the waves becoming smaller and more easily 

 compressible in proportion to the frequency of the 

 pulse, which generally counts from 100 to 120 and 

 more per minute at a comparatively early stage of the 

 poisoning process. But an equally potent cause of 

 heart failure is its depletion by the simultaneous 

 stagnation of the blood mass in the veins of the 

 abdomen. Finally, to complete the mischief, we have 

 not only anaemia of the semi-paralytic oblongata, but 

 the scanty blood supply this important centre receives 

 becomes also surcharged with carbonic acid. Oxyhse- 

 maglobin disappears almost entirely from the blood 

 under the circumstances detailed, as both pulmonary 

 and internal respiration are greatly interfered with, 

 the blood tending more and more towards that thin 



