yo Bulletin of Laboratories of Dcnison University [Voi. xii 



of brick which had not been soaked in meat juice in front of 

 them in the same way, but they paid no attention to them, or in 

 a few cases they would touch them with the barblets and then 

 swim away again ("tactile" reaction). They never attempted 

 to bite them. Clearly they taste the meat juice in the bricks 

 when they are touched by a barblet, and the experiment when 

 the body was touched by a similar brick held in forceps shows 

 that they taste the juice by the body also. 



On one occasion I tested the fishes with pieces of cooked 

 meat that had been long boiled so that nearly all the extractives 

 were drawn out. The experiments were conducted just like 

 those with the raw meat, but the fishes gave by no means so 

 clear reactions to it. Upon touching the sides of the body, the 

 fishes usually paid no attention to the stimulus, treating it just 

 as they did cotton. I then touched the barblets a few times 

 and to this they would generally react by turning and taking 

 the meat, but not always nor so promptly as with fresh meat. 

 Upon testing the sides of the body again after this experi- 

 experience, I got a reaction. The fishes would turn and touch 

 the meat with the barblet or lips before taking it, rarely giving 

 the quick reaction characteristic of fresh meat. Evidently the 

 cooked meat has less taste to the fishes than fresh meat and this 

 interferes with the reaction. They eat the cooked meat when 

 they are sure that it is edible. 



These experiments, which were all many times repeated 

 and controlled, I think show conclusively that practically the 

 whole cutaneous surface of Ameiiirus is sensitive to both tactile 

 and gustatory stimuli and that the latter call forth characteristic 

 reflexes which are of the greatest value to the fish in procuring 

 food. The fish normally reacts to contacts on the body by 

 both types of stimuli — to the mere tactile stimulus (if at all) by 

 a tentative movement calculated to bring the doubtful substance 

 into contact with the more highly sensitive barblets or lips, but 

 to the tactile stimulus accompanied by the gustatory by an im- 

 mediate, rapid and precise movement calculated to seize the 

 food. This latter reflex is unvarying and is very persistent un- 

 der a great variety of forms of stimulation. The former 



