THE TORPEDO 149 



regained by rest; it is also inci'eased by energetic circula- 

 tiun and respiration. As in muscular exertion the electri- 

 cal power is increased by the action of strychnine. 



Marey has more recently made interesting experiments 

 on the torpedo, examining the discharge of this fish with 

 the telephone. Slight excitations jjrovoked a short croak- 

 ing sound. Each of the small discharges was composed of 

 a dozen fluxes and pulsations, lasting about one fifteenth 

 of a second. The sound got from a prolonged discharge, 

 however, continued three to four seconds, and consisted of 



Fia. 191.— The Devil-fish. (Ceratoptera). From Latlcen's Zoology. 



a sort of groan, with tonality of about mi (165 vibrations), 

 agreeing pretty closely with the result of graphic experi- 

 ments. 



Marey has also studied the resemblance of the electrical 

 apparatus of the electrical ray or torpedo and a muscle. 

 Both are subject to will, provided with nei'ves of centrifugal 

 action, have a very similar chemical composition, and re- 

 semble each other in some points of structure. A muscle 

 in contraction and in tetanus executes a number of succes- 

 sive small movements or shocks, and a like complexity has 

 been proved by M. Mai-ey in the discharge of the torpedo. 



The sting-rays [Trygon) have no caudal fin, but the 

 spinal column is greatly elongated, very slender, and armed 



