194 ALBERT M. REESE 



be entirely swallowed or not, though as has been seen above, 

 the animal frequently swallows substances that would seem to 

 have no taste or smell whatever. They sometimes seem to 

 perceive by sight, objects, meat, etc., that are several centimeters 

 distant; but the telaesthetic sense apparently operates only 

 at much shorter distances. 



REACTIONS TO LIQUID CHEMICALS 



In the following experiments the reactions of the animals 

 to all of the chemicals used, representing the various tastes 

 as we know them, sweet, sour, bitter, etc., were tried in the 

 same way; the solutions, in varying strengths, were squirted 

 from a small pipette upon different parts of the animal as it 

 lay quiet in the bottom of the aquarium in about five centi- 

 meters of water. As the animals are naturally quite active, 

 especially in strong light, it was necessary to work in a rather 

 dim light. Owing to this same activity, the animals usually 

 became so restless after a few stimulations, that it was not possible 

 to make a large number of tests at any one time; this made 

 experimentation rather slow. 



Since the animals are only about nine centimeters in total 

 length, it was not possible to stimulate them in as many different 

 places as was done by Sheldon (8) with the dogfish. 



As a matter of fact, experiments failed to show, with the 

 exception of the anterior part of the head, any greater sensi- 

 tiveness in one part of the body over another. It was at first 

 thought that the region of the base of the tail was more sensitive 

 than any part except the head, perhaps because it was impossible, 

 because of the small size of the animal, to stimulate that region 

 without stimulating the region of the cloaca ; but further experi- 

 mentation failed to verify this early supposition. 



The reaction to all of the chemicals used, with the exception 

 of those described above under the head of food reactions, 

 were negative. In the case of sugar only was there no reaction, 

 and, in fact, even there a sort of negative reaction was seen, 

 as will be described later. 



The reaction when a chemical of sufficient strength was 

 squirted upon the tip of the head, varied from a slow with- 

 drawal backwards, when a very dilute solution was used, 

 to a sudden withdrawal accompanied with a violent shaking of 



