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 sensa- 

 tion is the brain, and to it the intelligence of any impression 

 made upon the nerves has to be transmitted before this 

 impression can become manifest in consciousness. The 

 transmission, moreover, requires time, and the consequence 

 is, that a wound inflicted 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 experi- 

 mental arrangement, Helmholtz has determined the velocity 

 of this nervous transmission, and finds it to be about one 

 hundred feet a second, or less than one-tenth of the velocity 

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

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

 till half a second after the wound had been inflicted. 1 But 

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

 scarcely be a doubt that to every act of consciousness be- 

 longs a determinate molecular arrangement of the brain 

 that every thought or feeling has its physical correlative in 

 that organ; and nothing can be more certain than that 

 every physical change, whether molecular or mechanical, 

 requires time for its accomplishment. So that, besides the 



1 A most admirable lecture on the velocity of nervous transmission 

 has been published by Dr. Du Bois-Raymond in the Proceedings of the 

 Royal Institution for 1866, vol. iv. p. 575. 



