[ 118 ] 



XVI. On the Wave-Lengths of the Transmission of Muscular and 

 Nervous Action. By the Rev. Samuel Haughton, M.D., 

 Fellow of Trinity College, Dublin. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



THE following result may prove of some interest to those 

 physiologists who are capable of applying it so as to draw 

 from it the consequences it seems capable of affording. 



(1) The rate of the muscular susurrus, first observed by Wol- 

 laston, and estimated by him at "from 20 to 30 in a second/* 

 has been fixed by Dr. Collongues of Paris, by means of tuning- 

 forks, at 35 in a second, and by myself, by means of organ- 

 pipes, at 32 in a second. 



(2) The rate of the tinnitus aurium, which is caused by the 

 action of the nerves, has been fixed by me at 1024 in a second. 



From these data, it follows that the rate of nerve actionis from 

 29 to 32 times as fast as the rate of muscular action. 



(3) The experiments of Dr. Schelske have shown that the 

 velocity of wave-transmission of sensation in the living body of 

 man is 97 feet per second. And, lastly, 



(4) The experiments of Professor Aebe, of Berne, prove that 

 the velocity of wave-transmission of muscular contraction in frogs 

 is 3 feet per second. 



The wave-transmission in the nerves is therefore 32 times 

 as fast as the wave-transmission in the muscles — or 29 times as 

 great if we adopt Helmholtz's determination of the rate of trans- 

 mission in the motor nerves of the legs of a frog, viz. 88 feet 

 per second. 



Now in any kind of wave-propagation, whether due to mecha- 

 nical or chemical changes, we have 



\=vt; 

 where 



\ is the wave-length, 



v is the wave-velocity, 



t is the rate of vibration, or period of the change. 



It appears from the preceding physiological experiments, taken 

 together, that v varies inversely as t when muscles and nerves 

 are compared; and consequently that X is constant : or 



The wave-length of the transmission of muscular and nervous 

 action is constant, and lies between 1*125 and 1*225 inch. 



If this conclusion be correct, important consequences ought to 

 follow from it ; for the nerves and muscles are so connected in 



