248 C. J. MARTIN. 
While with the control frogs there was no very marked altera- 
tion in the reflex excitability of the cord until the next day, those 
frogs in which the circulation was abolished failed to respond in 
twenty-five and twenty minutes after the suspension of the cireu- 
lation. For the few minutes previous to the absence of response 
to stimulation, the latent period was increased. The poisoned 
frogs whose hearts were still beating moderately after the cessation 
of all reflex activity, however, ceased to respond after fifteen and 3 
twenty minutes ; that is sooner than those in which the cord was 
deprived of all blood supply. Under these circumstances the 
effect on the nervous system must have been a direct one, and 
wholly independent of any interference with the vascular 
mechanism. 
(6)—The effect of the venom on motor nerves. 
The general features presented by an animal poisoned with the 
venom are strikingly similar to those which follow the injection 
of curari, The gradual cessation of all motor phenomena either 
of a spontaneous or reflex origin might very well be due to the 
poison operating in this way. The conclusion of Brunton and 
Fayrer, and Ragotzi, that cobra poison paralysed the peripheral 
ends of the motor nerves, lends additional support to such a view. 
With the object of investigating this point, I made a number 
of observations on frogs poisoned with the venom, in the same — 
way as the action of curari was determined by Claude Bernard. 
I also determined whether there was any evidence of such inter 
ference with the terminations of the phrenic nerves, and also” 
with the motor nerves of the brachial plexus of rabbits. Ragotat 4 
found that the terminations of the phrenics were more sensitive : 
to the action both of curari and of cobra poison, than the other 
motor nerve endings ; and he sees in this increased sensitiveness 
the reason why so many observers have attributed a selective 
action upon the respiratory centre to cobra venom. 
Ihave both with frogs and mammals been quite unable of ~ 
discover any indication that Pseudechis venom produces a0 
