40 Bulletin of Laboratories of Denison Unrirrsity L"^'"!- xrs 



We are, in fact, profoundly ignorant of the senses and in- 

 stincts of the fishes, even those connected with their feeding 

 habits which are of so direct importance to all commercial fish- 

 eries. Nearly all which one finds in the scientific literature 

 bearing on the senses of fishes is merely inference of function 

 based on a study of the structure of the organs — a most pre- 

 carious pathway for scientific research. My own studies on the 

 nerve components of fishes have led me to certain inferences 

 regarding the function and distribution of the organs of taste in 

 fishes, and the present study is an attempt to follow out these 

 inferences by the determination of more exact facts regarding 

 the pathways of gustatory stimuli as anatomically demonstra- 

 ble, together with sufficient direct physiological experiment to 

 furnish definite information of the function served by this sys- 

 tem of sense organs and of their nervous paths in the fishes. 



Neurologists have always paid a great deal of attention to 

 the conduction paths within the central nervous system, and in 

 recent years special efforts have been made to isolate the various 

 functional systems of neurones, tracing the exact path of the 

 sensory impulses from the peripheral organ to the primary sen- 

 sory center, thence to the various secondary centers and return 

 reflex paths. This motive underlies the recent studies on the 

 nerve components, and indeed much of the best morphological 

 work on the nervous system in all times. Some years ago I 

 formulated the following definition of such a functional system 

 of neurones, with special reference to the peripheral members 

 of the system: "The sum of all the nerve fibers in the bod)" 

 which possess certain physiological and morphological charac- 

 ters in common so that they may react in a common mode. 

 Morphologically each system is defined by the terminal rela- 

 tions of its fibers — by the organs to which they are related per- 

 ipherally and by the centers in which the fibers arise or termi- 

 nate. The fibers of a single system may appear in a large num- 

 ber of nerves repeated more or less uniformly in a metameric 

 way (as in the general cutaneous system of the spinal nerves), 

 or they may all be concentrated into a single nerve (as in the 

 optic nerve)." Now if we add to this the secondary paths re- 



