883 Royal Society : — 



" On the Action of Urari and of Strychnia on the Animal Eco- 

 nomy." By Professor Albert Kolliker of Wiirzburg. 



The communication which I now oifer to the Royal Society con- 

 tains a brief statement of the results of a series of experiments which 

 I lately made on the action of the urari poison and of strychnine on 

 the animal economy. 



I. Urari. 



The urari is the well-known poison from Guiana, also called 

 Curare and Woorara. That which I employed in my experiments 

 I owe to the liberahty of my friend Professor Christison of Edin- 

 burgh. The following are the conclusions at which I have arrived 

 respecting its operation : — 



1. The urari causes death very rapidly when injected into the 

 blood or inserted into a wound ; when introduced by way of the 

 mucous membrane of the intestinal canal its effects are slow and 

 require a large dose for their production, especially in mammalia, 

 AVhen applied to the skin of frogs it is altogether inoperative. 



2. Frogs poisoned with very small doses of urari may gradually 

 recover, even after it has produced complete paralysis of the nerves. 

 MammaUa may also be restored, even after large doses, provided 

 respiration is maintained artificially. 



3. The urari, acting through the blood, destroys the excitability 

 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 poisonmg (as in No. 4), 

 it is found that the cord retains its rejlex 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 



