2o6 Journal of Comparative Neurology and Psychology . 



second (for the centrifugal), and in the hypoglossus nerve 10.5 m. per 

 second, (3) observation that the brain is able to execute apparently 

 conscious functions at least two and a half hours after separation from 

 the spinal cord. E. m. y. 



Kiesow, F. Contribution a I'etude dela v^locite de propagation du stimulus 

 dans le nerf sensitif de 1' homme. Archives Italiennes de Biologie, t. 40, 

 pp. 273-2S0, 1903. 



By carefully measuring the reaction-time of thoroughly trained 

 subjects to tactual stimuli applied at different regions of the arm or leg 

 Kiesow has succeeded in showing to his satisfaction that the rate of 

 transmission in the sensory nerves of man is practically the same as 

 for the motor nerves, 30 to 33 m. per second. 



The work is very clean cut, and the results are so uniform that 

 one cannot doubt the truth of the author's conclusions. k. m. y. 



Motora, Yujiro. A Study on the Conductivity of the Nervous System. Amer. 

 Jour. Fsy., Vol. 14, pp. 329-350, 1903. 



This is a brief discussion of theories of nerve conduction, and a de- 

 scription of certain experiments upon which the author bases his so-called 

 hydraulic theory. 



For the facts of nerve transmission, he writes : "I propose an 

 hydraulic explanation. It supposes that nervous conduction is a trans- 

 mission of a water wave in a protoplasmic tube and that the protoplas- 

 mic tube not only helps the transmission by its own elasticity but is 

 excitable at any point by means of a stimulus directly applied to it." 



Motora experimented with water-filled tubes under various con- 

 ditions, to determine whether the phenomena characteristic of nerve 

 conduction are exhibited also by them. The experiments deal with 

 the following topics : Experiment i — Rate of transmission of water 

 wave in rubber tubes. It was found to be about 100 feet per second, 

 or approximately the same as the nerye rate. Experiment 2 — Evi- 

 dence of an action current. Under certain conditions, we are told, 

 the wave in a tube filled with slightly acidulated water is accompanied 

 by what appears to be a thermo-electric current. The author writes 

 concerning the action current in the nerve, "I believe that the action 

 current is explicable as a thermo-electric current produced between 

 two points of the nerve where the electrodes touch it." Experiment 3 

 — Inhibition phenomena. This study of the interference of water 

 waves leads the author to the conclusion, that the phenomena of atten- 

 tion and inhibition "are very conveniently explained under the sup- 

 position of a protoplasmic tube" (filled with fluid). 



