SENSE OF TASTE. 



895 



Only four different varieties of taste can be distinguished. Sub- 

 stances may be either bitter, sweet, acid, or saline. Substances to 

 which we attribute the property of flavor owe that characteristic more 

 to their implication of the sense of smell than of taste. Thus, we speak 

 of tasting wines, onions, asafeticla, and so on, while, as is well known, 

 their flavor is due to the excitement of the sense of smell, and not to a 

 specific stimulation of the nerve of taste ; this may be readily proven by 

 the disappearance of their characteristic flavors when smell, by closure 

 of the nostrils or by catarrh, is rendered impossible. 



That substances may be tasted it is necessary, in the first place, 



FIG. 411. STRUCTURE OF THE GUSTATORY ORGANS. (Munk.) 



A, perpendicular section through the taste organs of a rabbit's tongue; g, taste furrows. B, isolated 

 protective (a) and (b c) taste cells. 



that they should be dissolved in the fluids of the mouth, while the 

 intensity of the sensation will depend upon the size of the surface acted 

 upon and upon the concentration of the solution. It has been found 

 that the following series of substances cease to be distinguished in the 

 order here stated, as the}' are gradually diluted : syrup, sugar, common 

 salt, aloes, quinine, and sulphuric acid. Thus, quinine may be diluted 

 twenty times more than salt and still be distinguished. 



The time elapsing between the contact of the substance with the 

 tongue and its appreciation by the taste also varies with different 

 substances. Saline substances are tasted most rapidly, perhaps, from 

 their more rapid diffusion. 



