201 



Without attaching much value to either hypothesis, the author 

 prefers the latter, and remarks in conclusion that there can be little 

 doubt that many new series of organic acids may, by analogous pro- 

 cesses, be produced from inorganic acids by the replacement of one 

 or more atoms of oxygen by an alcohol radical ; in fact his pupil, 

 Mr. Hobson, is now engaged in the study of a new series containing 

 sulphur, produced by the action of zincethyl and its homologues 

 upon sulphurous acid. These acids are formed by the replacement 

 of one equivalent of oxygen, in three equivalents of sulphurous acid, 

 by an alcohol radical. 



IX. " On the Action of Urari and of Strychnia on the Animal 

 Economy." By Professor ALBERT KOLLIKER of Wiirz- 

 burg. Communicated by Dr. SHARPEY, Sec. R.S. Re- 

 ceived May 31, 1856. 



The communication which I now offer 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 strychnia 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 liberality of my friend Professor Christison of Edin- 

 burgh. The following are the conclusions at which I arrived respect- 

 ing 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. 

 When 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. 

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

 respiration is maintained artificially. 



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



