XXI 



DEATH BY LIGHTNING 



PEOPLE in general imagine, when they think at all 

 about the matter, that an impression upon the 

 nerves — a blow, for example, or the prick of a 

 pin — ^is felt at the moment it is inflicted. But this is 

 not the case. The seat of sensation being the brain, to it 

 the intelligence of any impression made upon the nerves 

 has to be transmitted before this impression can become 

 manifest as consciousness. The transmission, moreover, 

 requires time^ and the consequence is, that a wound in- 

 flicted on a portion of the body distant from the brain is 

 more tardily appreciated than one inflicted adjacent to the 

 brain. By an extremely ingenious experimental arrange- 

 ment, Helmholtz has determined the velocity of this ner- 

 vous transmission, and finds it to be about eighty feet a 

 second, or less than one-thirteenth of the velocity of 

 sound in air. If, therefore, a whale forty feet long were 

 wounded in the tail, it would not be conscious of the in- 

 jury till half a second after the wound had been inflicted.* 

 But this is not the only ingredient in the delay. There 

 can scarcely be a doubt that to every act of consciousness 

 belongs a determinate molecular arrangement of the brain 



* A most admirable lecture on the velocity of nervous transmission has been 

 published by Dr. Du Bois-Reymond in the "Proceedings of the Royal Institu- 

 tion" for 1866, vol. iv. p. 675. 



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