1898] RUDIMENTARY NERVOUS SYSTEM 335 



formed by Savart at the College de France seen the shape of some 

 liquid veins change abruptly under the influence of musical notes 

 entirely inappreciable to the ear, that were played at the Luxembourg. 

 2. The figures below are most interesting : 



Velocity of light . 300,000,000 metres a second, 



electricity 180,000,000 



„ sound . 331 „ 



„ liquid waves 1 10 „ 



„ nervous vibrations (Lobster) 8 „ (Fredericq) 



'* 11 ne faut pas confondre la pulsation, l'arrivee d'une onde, avec 

 le mouvement de la circulation lui-meme ; on ne pent trop le 

 rcpeter : \uida non est materia progrcdiens, seel forma materiae 

 progredientis : aussi Czermak a prouve, par des recherches tres exactes 

 (sphygmographe a miroir), que tandis que le mouvement du sang 

 diminue de vitesse a mesure qu'on se rapproche des capillaires, la 

 vitesse de propagation de l'onde pulsative va au contraire en aug- 

 mentant du centre a la peripheric. Onimus a insiste sur ces 

 caracteres de l'onde pulsative." (Etudes sur les traces obtenus 

 par le sphygmographe. Journal d' anatomic, 1866.) 2 



It is then extremely probable that a nervous vibration is nothing 

 more than a molecular one, the velocity of which varies in accord- 

 ance with its conditions, though it never amounts to more than 

 thirty or ninety metres per second. Here are some other proofs: 



.">. I modified Secchi's classical experiment 3 of pouring a few 

 drops of alcohol on a thin bed of water, by substituting for the 

 former a mixture of alcohol and castor oil, and adding to the water 

 a considerable quantity of linseed oil. Under these conditions a 

 strong agitation takes place. In like manner Longet provoked some 

 local convulsions by touching the motor nerves with alcohol. 4 



4. In most cases mechanical excitation affords real and genuine 

 success, 5 and the excitability of the Helix nerves can only be 

 evidenced by means of mechanical and physical irritants. (Milne- 

 Edwards.) 



In some animals diverse concretions are present, which oscillate 

 at the least agitation of the external fluid, and increase the mechanic 

 vibration endured by the auditive nervous terminations, rather than 

 translate any currents endowed with a mysterious nature. 



I have made a small apparatus tending to demonstrate the in- 

 fluence exercised by otoliths on the vibrations of mercury. It con- 



1 Marey. Mouvements des ondes liquides dans les tubes elastiques. Journal de 

 physique, 1875, Vol. ix., p. 2.">7. 



- Kiiss et Duval. Conrs de physiologie, Paris, 1879, p. 259. 



3 L'unite des forces physiques, Paris, 1874, p. 73. 



4 Traite de physiologic, Paris, 1869, Vol. iii., p. 209. 

 Beclard. Traitd de physiologie, p. 961. 



8 Chatin. Les organ.- des sens, p. 301. 



