192 



Adaptations of Fishes 



of the body. But when a current strong enough to be quite 

 painful to the hands while handling the electrodes was used 

 then stimulation of the fish called forth a brilliant glow of light 

 apparently from every well-developed photophore. All the 

 lines on the ventral and lateral surfaces of the body glowed 

 with a beautiful light, and continued to do so while the stimu- 

 lation lasted. The single well-developed organ just back of 

 and below the eye was especially prominent. No luminosity 

 was observed in the region of the dorsal organs previously de- 

 scribed as rudimentary in stmcture. I was also able to produce 



, mo 



Tnd 



FIG. 146. Luminous organs and lateral line of Midshipman, Poric/U/iys notatus 

 Girard. Family Batrachoididce. Monterey, California. (After Greene.) 



the same effect by galvanic stimulation, rapidly making and 

 breaking the current by hand. 



" The light produced in Porichthys was, as near as could be 

 determined by direct observation, a white light. When pro- 

 duced by electric stimulation it did not suddenly reach its 

 maximal intensity, but came in quite gradually and disappeared 

 in the same way when the stimulation ceased. The light was 

 not a strong one, only strong enough to enable one to quite 

 easily distinguish the apparatus used in the experiment. 



" An important fact brought out by the above experiment is 

 that an electrical stimulation strong enough to most violently 

 stimulate the nervous system, as shown by the violent con- 

 tractions of the muscular system, may still be too weak to 

 produce phosphorescence. This fact gives a physiological con- 



