336 NATURAL SCIENCE [November 



sists of a drum full of water, having some artificial otoliths prepared 

 after Bay's method 1 (fig. 16). 



It is quite surprising that the study of auditive phenomena, or 

 more properly speaking, that of the vibrations of auditive nervous 

 terminations, has not already suggested the explanation of the im- 

 portant facts connected with innervation. 



5. Compression abolishes the function of the natural nerve as 

 well as that of the nerve of mercury, but the aforesaid function may 

 be re-established when compression has not disorganised its anatomical 

 elements deeply or divided the thread of mercury (fig. 6). Richet 

 says 2 that an analogy between blood circulation and nervous con- 

 ductibility might be established : " Quand on applique une pince sur 

 une artere, on interrompt le cours du sang, qui se retablit des qu'on 

 enleve la pince." 



The facts regarding transmission of electricity, heat, etc., are 

 completely different. 



6. If this or that excitation provokes this or that sensibility, it 

 probably takes rise not in the nature of the nerve itself, but in its 

 connections with these or those centres. (Richet.) 



7. The wave increases in bulk as a sort of avalanche in the 

 course of its progress through the nerve (Pfliiger) and the thread of 

 mercury (fig. 7). The phenomena may easily be observed by fixing 

 several equidistant levers, so that they may rest on the metallic 

 surface lightly (fig. 3). 



8. The variations consequent on temperature are probably due 

 to the variations of density of the band axis in the formula 



/ r 



for whenever d increases e cools and v diminishes ; and may also 

 be due to the duration afforded to the continuance of the muscle's 

 latent excitation (Marey), or to the discharge of carbon dioxide. 



9. Richet regarded negative variation of carbon dioxide as a 

 testimony to the nerve's mechanical vibration. 3 They both have nearly 

 the same amount of velocity. Dr R. Jofre, Director of the Laboratory 

 of Medical Electricity, reminds me of similar and considerable 

 modifications of current taking place in microphones, as a sequence 

 to the mechanical vibrations and insignificant stirrings occasioned 

 by an insect's walk for instance. 



" La surface inferieure du lobe sensitif de la Dionee attrape- 

 mouches est electro- negative par rapport a la surface superieure, au 

 moment ou la feuille est irritee : au bout d'une demi-seconde, la sur- 



1 Carpenter. The Microscope and its Revelations. London, 1868, p. 775. 



- Richet. La vibration nerveuse. Revue Scientifique, Juillet a Decembre 1882, p. 99. 



3 Milne-Edwards, I.e., Vol. xiii., p. 5. 



