624 ANIMAL PHYSIOLOGY. 
placed on the tongue, a sensation of taste is aroused, described 
differently by different persons; also when the tongue is quick- 
Fia. 465.—Papille of tongue (after Sappey). 1, circumvallate papille ; 3. fungiform papille ; 
4, filiform papilla ; 6, glands at base of tongue ; 7, tonsils. 
ly tapped, showing that, though taste is usually the result of 
chemical stimulation, it may be excited by such as are electrical 
or mechanical. 
But it is not to be forgotten that we have usually no pure 
gustatory sensations, but that these are necessarily blended 
with those of common sensation, temperature, etc., and that our 
judgments must, in the nature of the case, be based upon highly 
complex data, even leaving out of account other senses such as 
vision. 
