Landacre, Taste Buds of Ajnenirus. 3 



In the brief historical outline which follows no attempt is made 

 to give a digest of the earlier literature on the cranial nerves of 

 fishes, much of which is confusing and still more of which is of 

 little value for the present purpose, owing to the fact that it de- 

 pends for its analysis of the cranial nerves on the method of gross 

 dissection, a method which is totally inadequate where it is pos- 

 sible to separate the various components only by a microscopic 

 study of serial sections. 



The review of the theory of nerve components makes no claim 

 to completeness either, it being the writer's intention to present 

 the salient points of that theory as far as they would be of value 

 for the present paper, which is concerned solely with the com- 

 munis system. For a comparison of the results of the micro- 

 scopical analysis of the cranial nerves with the earlier attempt by 

 gross methods the reader should consult the papers of Strqng, 

 Herrick, Johnston, Kingsbury, Cole and others. 



(a) Taste or Terminal Buds. — The taste buds were first dis- 

 covered on the palatal organ of the carp in 1827 by Weber ('27) 

 and their function correctly inferred. In 1851 Leydig ('51) dis- 

 covered the taste or terminal buds on the outer skin of fishes but 

 gave a somewhat faulty description. In 1863 F. E. Schulze 

 ('63) described the same organs and distinguished structurally 

 between the sensory and supporting cells and inferred their func- 

 tion to be the same as similar buds found inside the mouth. The 

 same author showed in 1870 that the terminal or taste buds differ 

 in structure from the lateral line organs or neuromasts of what- 

 ever form in that the sensory cells of the taste buds are elongated 

 cells and pass down from the surface of the epithelium entirely 

 to the basement membrane, while the sensory cells of the lateral 

 line organs and of all superficial organs related to them are pear- 

 shaped and do not reach the basement membrane. 



Merkel ('80) in 1880 confirmed these structural differences, 

 but confused the subject by attributing the same function, namely, 

 touch, to both terminal or taste buds and neuromasts or lateral 

 line and related organs. 



In 1904 C. J. Herrick ('04) demonstrated by experiments 

 that the function of the terminal buds is undoubtedly gustatory, 

 and in addition showed that the cat fishes, at least, can locate 

 sapid substances by the sense of taste and can learn to distinguish 

 between gustatory and tactile stimuli, although ordinarily these 



