336 NATURAL SCIENCE [November 
sists of a drum full of water, having some artificial otoliths prepared 
after Ray’s method * (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 mnercury, 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” that an analogy between blood circulation and nervous con- 
ductibility might be established: “ Quand on applique une pince sur 
une artére, on interrompt le cours du sang, qui se rétablit dés qu’on 
enléve 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 (Pfltiger) 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 
d 
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.? 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 inférieure du lobe sensitif de la Dionée attrape- 
mouches est ¢lectro-négative par rapport a la surface supérieure, au 
moment ou la feuille est irritée: 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 1 Décembre 1882, p, 99. 
3 Milne-Edwards, l.c., Vol. xiii., p. 5. 
