REPORT OF THIRTEENTH ANNUAL MEETING. 19 



relatively meaningless, because imperfectly understood, inco- 

 ordinated. In our third t}'pe of method, on the other hand, it is 

 easier to correlate the data as we go along, the synthesis accom- 

 panies the analysis, and the possibility of experimental control 

 should keep the student in closer touch with his guiding facts and 

 discourage general speculation. 



As a concrete illustration of the practical method of applying 

 the doctrine of nerve components in the functional analysis of the 

 nervous system, we may summarize briefly the progress which 

 has been made up to date in the study of the gustatory: system. 



In man, as is well known, the sense of taste is not very 

 highly developed. The peripheral organs, or taste buds, are situ- 

 ated chiefly on the tongue, those near its base innervated by the 

 glossopharyngeal nerve, and those near the tip probably by the 

 chorda tympani of the facial nerve. But the gustatory pathway 

 toward the brain is very imperfectly understood and many points 

 are still in controversy, while the central path is almost wholly 

 unknown. 



But in certain fishes, such as the carp and cat fish, this 

 system of sense organs is enormously exaggerated. Taste buds 

 are found, not only in the mouth, but all over the outer skin and 

 barblets. Direct experiment shows that these fishes actually do 

 ' taste with these superficial sense organs — unlike some people, their 

 taste is not all in their mouth. 



The experiments made on the cat fish (Ameiurus) show that 

 these fishes seek their food by feeling for it with the barblets and 

 by means of them they discriminate between edible and non-edible 

 substances, that they habitually use both the sense of touch and 

 the sense of taste for the purpose and that they can iDe taught to 

 discriminate between tactile and gustatory stimuli applied to the 

 skin and will turn and snap up savory substances and reject objects 

 which feel like them but are devoid of taste. 



The exact distribution of the gustatory sense organs has been 

 determined and their nerves traced back to the brain. We get the 

 gustator}^ reaction from the skin as described above in fishes 

 which possess these cutaneous sense organs, and the reaction is not 

 obtained from fishes which do not possess such sense organs and 

 nerves. 



All of these cutaneous sense organs are innervated from a 

 single nerve, the sensory root of the facial (corresponding to 

 the portio intermedia of human anatomy), which is the biggest 

 nerve in the bod}'. The center in which this nerve terminates 

 in the medulla oblongata is about as big as the entire forebrain. 



