SiGERSON — On the Study of Nerve- Action. 257 



XLIII. CoNTErBTJTIO^rS TO THE StUDT OP l^EUVE- ACTION IN" CO>'NEXION- 



WITH THE Sense of Taste. I. — FtrNCTioN of the Tbigemtntjs. By 

 Geokge SiGfEESour, M. D., Ch. M., P. L. S. 



[Read, June 23, 1879.] 



It is a remarkable fact that, whilst the study of some of the special 

 senses, such as those of sight and hearing, has made great progress, 

 that of the sense of taste remains still in a very imperfect condition. 

 The difficulties in the way of its elucidation are eyidently consider- 

 able, for we find that contradictory results have been arrived at by 

 various observers of repute. Unquestionably much advance has been 

 made since the physiological doctrine, as stated by Boerhaave and 

 Duverney, was in unison with popular opinion, in regarding the 

 tongue as the only seat of taste. De Jussieu, disturbing that con- 

 cordance, placed physiology on the true path of research when he 

 pointed out that taste was still preserved after the excision of the 

 tongue, and that it was present in those from whom the tongue was 

 congenitally absent. These pathological facts proved, not of course 

 that the tongue was devoid of this special sense, but that other parts 

 within the buccal cavity possessed the power of distinguishing sapid 

 impressions. "When, however, it became a question of differentiating 

 and localising the taste-power, the difficulties increased with the 

 accumulation of facts. Hence, even at the present day, most points 

 of importance in connexion with this subject should be looked upon 

 as still in dispute, if we are to accept the statement embodied in the 

 most recent edition of a standard physiological work. Professor 

 Hermann^ of Zurich, having mentioned that it is difficult to separate 

 the taste-sense from simultaneously evoked odorous and tactual sen- 

 sations, and to strictly localise the test-fluid, makes the following 

 statement : — " The special seat of the gustatory sensibiKty has there- 

 fore been very differently stated. Undoubtedly, the root of the 

 tongue plays an important part, but it is doubtful whether it alone 

 (Bidder, Wagner), or also the tip and the borders of the tongue 

 ' (Schirmer, Klaatsch, Stich, and Camerer), the soft palate (J. Mtiller, 

 Drielsma), or at least a part of it (Schirmer, Klaatsch, and Stich), 

 or even the hard palate (Drielsma), are seats of gustatory sensa- 

 tion." 



The method of research by means of physiological experimentation 

 on animals affords us only a limited assistance ; for, as animals cannot 

 give us an intelligible expression of their sensations in this matter, 

 the results obtained are often unsatisfactory, and have sometimes 

 proved misleading. Undoubtedly many valuable facts have thus been 

 acquired, but it seems almost impossible, by this method, to distin- 



^ Hermann, Elements of Human Fhysiology, p. 458, London, 1878- 



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