OP TASTE. 427 



become so benumbed as to be unable to distinguish some altogether. 

 Thus Turner found "that the flower -of the iris persica was Various effects 

 pronounced of pleasant odor by forty-one out of fifty-four of odorous im- 

 persons, by four to have little scent, and by one to be ill- P rtessions - 

 scented. Of thirty persons, twenty-three held the anemone nemorosa 

 agreeable in its perfume, and seven did not think that it smelled at all." 

 Diseases of the central organs will sometimes give rise to the percep- 

 tion of subjective odors, just as they do to spectral illusions or subjective 

 sounds in the ears. odors. 



CHAPTER XXIV. 



OF TASTE. 



Conditions for Taste. Structure and Functions of the Tongue. Tactile and Gustative Regions 

 of the Tongue. Complementary Tastes. Subjective Tastes. 



THOUGH the function is participated in by other portions of the oral 

 cavity, the tongue is to be regarded as the organ of taste. Conditions for 

 The physical conditions under which savors are perceived is taste - 

 that the substance shall be presented in solution in water, or, at all 

 events, in the saliva. From vision, hearing, and smell, the sense of taste 

 differs in the circumstance that it requires the contact of the acting body; 

 and, to a certain extent, the same distinction which has been made re- 

 garding such substances as can act on the olfactory mechanism might 

 also be made here ; that is to say, that there are two classes of agents 

 which affect the organ those which produce a mere pungent sensation, 

 and those which excite savors, properly speaking, for the irritations and 

 former will frequently give rise to specific action when ap- savors- 

 plied to other portions of the surface of the skin. 



Sensations of taste are very frequently conjoined with olfactory per- 

 ceptions, so that we mistake the one for the other. There Connection of 

 are many substances, reputed to have a powerful flavor, ceptkmTand" 

 which become tasteless when the nose is held ; and this re- tastes. 

 mark applies more particularly to such as are at the same time volatile 

 and soluble in water. However, irrespectively of this, some of those 

 bodies which produce the most intense and permanent impression on the 

 organs of taste do so merely in virtue of their solubility, as, for exam- 

 ple, quinine, which is a non-volatile body. The intensity of such action 

 depends on the duration of contact and the degree of exposure of the 

 substance to the tongue, so that the papilla? may, as it were, become 

 thoroughly permeated. 



