ZOOLOGY. 



VELOCITY OF THE NERVE FORCE. 



At the September (1862) meeting of the Societe Helvetique des 

 Sciences Naturelles, M. Hirseh exhibited an apparatus for determin- 

 ing what astronomers call the personal equation of time, or the differ- 

 ence which observers make from personal causes in the estimation of 

 minute periods. He said, " We have now introduced the electric 

 method into astronomical observation, and as the observer has only to 

 shut off the current as soon as he sees the bisection of a star, the 

 problem of personal equation consists in determining the time which 

 is necessary for the astronomer to see and execute the necessary 

 movement of his finger. This time, which we call physiological time, 

 consists of three elements: 1. The time occupied in transmitting the 

 impression to the brain ; 2. The time taken by the brain to transform 

 the sensation into a volition, and, 3, that consumed in transmitting 

 this volition through the nerves, and in the execution of the muscular 

 movement." To ascertain these minute periods, M. Hirseh employs 

 the chronoscope of M. Hipp. A ball is so arranged that its fall inter- 

 rupts an electric current, and thus sets free the motion of certain 

 hands. As soon as an observer perceives the fall of the ball, he re- 

 rnake^ the contact, and arrests the hands, whose motion in the interval 

 gives the physiological time. By the use of this instrument M. Hirseh 

 has come to the conclusion that nerves transmit their impressions at 

 the rate of thirty-four metres a second. Mr. Heimholz estimated 

 their velocity at one hundred and ninety feet per second, but his 

 experiments were on the motor nerves of frogs, and those of M. 

 Hirseh on the sensitive nerves of man. 



HAIRLESS MEN OF AUSTRALIA. 



The Sydney Empire (Australia), of February 19th, 1862, publishes 

 the following curious account of a race of bald men, recently discov- 

 ered in that island-continent. It says : 



" It is now some few years since a report first obtained currency, 

 that, far in the western interior, beyond the Balonno River, a tribe 

 of aboriginal natives existed who exhibited remarkable physical dis- 

 tinctions from those with whom explorers and other colonists have so 

 long been familiar. It was said that the natives in question were en- 

 tirely destitute of hair, even on the head, which was as bald as a 

 billiard-ball. Other remarkable peculiarities were also mentioned, 



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