THEIE NATDBE AKD EFFECTS. 33 



contractions in various groups of muscles. They, 

 however, are not so well marked as those produced by 

 stimulation of the respiratory centre, but they are 

 equally rapidly followed by complete paralysis. 



Action of Cobra-Poison on the Respiration. 



The action of cobra-poison on the respiratory func- 

 tion deserves the closest attention, as deiUli is generally 

 the direct result of the extinction of this function by 

 the effect of the poison. 



The first change that is noticed in the breathing of 

 an animal after the introduction of cobra-poison, is a 

 decided quickening and deepening of the respiratory 

 movement. This effect is no longer to be perceived 

 after section of the vagi, and it has been asserted 

 that the acceleration is due to the stimulation of 

 those nerves by the poison. But section of the vagi is 

 always followed by excessive slowing of the respiratory 

 movement ; thus, in dogs, the respirations are generally 

 reduced by one-half. It is not improbable, therefore, 

 that an agent that would somewhat stimulate and 

 accelerate the action of the respiratory centre, would 

 fail in producing this result if administered directly 

 after an operation that had so powerfully retarding 

 effect. The inhibitory effect of section of the vagi may 

 be too great to allow of the accelerating action of the 

 poison being perceived. But this quickening, however 



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