']6 Bulletin of Laboratories of Dcnison University. [Voi xii 



ries might be followed by an incomplete reaction, but after 

 that usually no notice was taken of the cotton. The fishes 

 apparently remembered the preceding tests. But if more than 

 24 hours intervened between tests, the process of training- 

 usually had to be gone over again. 



The fact that the hake does not appear to remember the 

 difference between the pure tactile stimulus, and the tactile plus 

 the gustatory for so long a time as the cat fish does is probably 

 to be explained by the fact that the number of taste buds on 

 the filamentous fins of the hake is much less than that on the 

 barblets of the cat fish and therefore the gustatory element in 

 the sensation complex is doubtless much less in the hake. The 

 whole course of experiments indicates that the response is in 

 fact much more strongly tactile in the hake. 



During the course of these experiments I often alternated 

 bits of meat with the cotton wool, and at other times sub- 

 stituted cotton that had been soaked in clam juice. In these 

 cases I always got the characteristic gustatory reaction by all 

 of the filamentous fins, no difference being observable between 

 the reaction to meat of clams or fish and that to cotton soaked 

 in filtered clam juice. 



I also tested the hake with gelatin which had been soaked 

 up in cold water. Shreds of the well softened gelatin were 

 fastened to the end of a wire and brought into contact with the 

 body surface. The reactions were identical with those obtained 

 with white cotton. The gelatin shreds are very nearly colorless 

 and absolutely tasteless to my tongue. But to the sense of 

 touch they are almost exactly the same as the bits of fresh clam 

 meat with which most of these experiments have been con- 

 ducted. The hake at first would take the bait when the fila- 

 mentous dorsal was touched, but if the gelatin was taken into 

 the mouth it would be immediately rejected and after a few 

 trials the fish would no longer respond to the stimulus. He 

 acted in the same way when the pelvic fins were stimulated. 

 Shreds of the softened gelatin falling through the water were 

 sometimes noticed, but rarely taken into the mouth, and if so 

 were immediately rejected. Similar shreds lying on the bottom 



