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of the motor nerves. In frogs under its operation the terminal 

 branches of these nerves within the muscles lose their excitability 

 in a few minutes, whilst their trunks become affected an hour or two 

 later. If, after the nervous extremities have become paralysed, the 

 heart of the animal be excised so as to prevent the nerves from 

 receiving any further share of the poison, the nervous trunks may 

 retain their excitability for three or four hours. 



4. The brain is less affected by the urari than the nerves in the 

 muscles ; still when, by ligature of the two aortic arches, in frogs, 

 the poisoning is confined to the anterior half of the body, the volun- 

 tary movements of the limbs speedily cease, whilst automatic move- 

 ments, of doubtful nature and probably proceeding from the medulla 

 oblongata, may be still observed for half an hour or an hour after 

 the poison has begun to operate. 



5. The spinal cord is considerably less affected than the brain by 

 this poison, and by local limitation of the poisoning (as in No. 4), 

 it is found that the cord retains its reflex activity from half an hour 

 to an hour and a half, and the excitability of its white substance or 

 its conducting power from two to three hours after the poison has 

 taken effect. It is worthy of remark that in such cases the impaired 

 reflex activity of the spinal cord may be revived by strychnia directly 

 applied to it. 



6. The sensory nerves, as shown also by locally limited poisoning, 

 retain their functional activity as long at any rate as reflex actions 

 can be excited, and when the depressed reflex activity has been 

 revived by means of strychnia, these nerves are found not to have 

 been in the slightest degree injured, so that it seems doubtful 

 whether the urari in any way affects them. 



7. The nerves of the involuntary muscles and of the glands are also 

 paralysed by the action of urari, at least I find this to be true in the 

 following cases, viz. 



a. The pneumogastric, as regards its influence on the heart. 



b. The sympathetic (its cervical portion), in its relation to the 

 iris. 



c. The nerves of the posterior lymph-hearts of the frog. 



d. The nerves of the vessels in the web of the frog's foot. 



e. The splanchnic nerves of the rabbit, as affecting the peristaltic 

 motions. 



