SCIKNCE AND MAN. 609 



The quickness of thought has passed into a proverb, and 

 the notion that any measurable time elapsed between the 

 infliction of a wound and the feeling of the injury would 

 have been rejected as preposterous thirty years ago. 

 Nervous impressions, notwithstanding the results of 

 Haller, were thought to be transmitted, if not instantane- 

 ously, at all events with the rapidity of electricity. Hence, 

 when Helmholtz, in 1851, affirmed, as the result of experi- 

 ment, nervous transmission to be a comparatively sluggish 

 process, very few believed him. His experiments may 

 now be made in the lecture-room. Sound in air moves 

 at the rate of 1,100 feet a second; sound in water moves 

 at the rate of 5,000 feet a second; light in ether moves at 

 the rate of 186,000 miles a second, and electricity in free 

 wires moves probably at the same rate. But the nerves 

 transmit their messages at the rate of only 70 feet a second, 

 a progress which in these quick times might well be 

 regarded as inordinately slow. 



Your townsman, Mr. Gore, has produced by electrolysis 

 a kind of antimony which exhibits an action strikingly 

 analogous to that of nervous propagation. A rod of this 

 antimony is in such a molecular condition that when you 

 scratch or heat one end of the rod, the disturbance propa- 

 gates itself before your eyes to the other end, the onward 

 march of the disturbance being announced by the develop- 

 ment of heat and fumes along the line of propagation. In 

 some such way the molecules of the nerves are successively 

 overthrown; and if Mr. Gore could only devise some means 

 of winding up his exhausted antimony, as the nutritive 

 blood winds up exhausted nerves, the comparison would be 

 complete. The subject may be summed up, as Du Bois- 

 Reymond has summed it up, by reference to the case of a 

 whale struck by a harpoon in the tail. If the animal 

 were 70 feet long, a second would elapse before the disturb- 

 ance could reach the brain. But the impression after its 

 arrival has to diffuse itself and throw the brain into the 

 molecular condition necessary to consciousness. Then, 

 and not till then, the command to the tail to defend itself 

 is shot through the motor nerves. Another second must 

 olapse before the command can reach the tail, so that more 

 than two seconds transpire between the infliction of the 

 wound and the muscular response of the part wounded. 

 The interval required for the kindling of consciousness 



