904 



exhausted under the action of stimulants, the longer the period that 

 has elapsed since its detachment. 



The author then proceeds to relate the nature of the strict analogy 

 existing between electricity and nervous force. As electricity is de- 

 veloped under the influence of the nervous current in the organs of 

 electrical fishes, so, as a converse of this phenomenon, electricity 

 may develope the nervous force. After adverting to the well-known 

 analogy subsisting in every particular between the phenomena of 

 the electrical organ and those of musclesj he adverts to the old ex- 

 periment of passing a current through the muscles of the thighs of 

 a living animal, the positive pole being placed now above, now below, 

 so that it may be supposed that the current passes in the two cases 



■ in opposite directions as regards the nervous filaments distributed in 

 the muscles. He then points out that the efi'ects of a current 

 directed downwards, in the direct course of the nerves, are a strong 

 contraction of the muscle traversed, and also of the muscles of the 

 leg below ; while the effect of a current in the opposite, or inverse 

 direction, \s paiii, together with contractions less violent and ahvays 

 confined to the muscles traversed. The contractions (especially of 

 the parts below^) indicate a current of nervous force propagated to- 

 wards the muscles, while th.e pain indicates a current towards the 

 nervous centre. Now, bearing in mind that it has been proved by 

 direct experiments that an electric current traversing a muscle never 

 quits the muscular fibre to enter the nervous filaments, it seems clear 

 that the phenomena just spoken of are exclusively owing to the in- 



Jiuence exerted by the electricity passing through the muscles on 

 the nervous force contained in the nerves ; and also that this nervous 

 force acts peripherad or centrad according to the direction of the 

 electric current which excites it. The great importance of the con- 

 clusions drawn from these experiments consists in this, that they lead 

 to the same law which establishes the analogy between nervous force 

 and the electrical discharge of fishes. The paper concludes with 

 some further considerations intended to confirm this law. 



January 17, 1850. 

 SIR RODERICK I. MURCHISON, Vice-President, in the Chair. 



A paper was read, entitled " Researches respecting the Molecular 

 constitution of the Volatile Organic Bases." By Dr. A. W. Hofmann. 

 Communicated by Sir James Clark, Bart., F.R.S. 



Chemists, although all acknowdedging the existence of an intimate 

 relation between the vegetable alkaloids and ammonia, are nevertheless 

 divided in their opinions respecting the nature of this connection, 

 two theories having been propounded upon the subject. According 

 to the one, that of Berzelius, the bases would have to be considered 

 as conjugated amujonias in which ammonia still pre-exists as such ; 

 while according to Liebig's views, these substances are represented as 



