Minute Anatomy of tie 
where the parts are so beautifully distinct in sections under the 
microscope. 
As in the experiments on mammalia, in which the glossopha- 
ryngeal nerve, when excited indirectly, influences the contiguous 
muscles and vessels from afferent and efferent fibres at the spinal 
end and ganglionic system, so we find we have here within a very 
small compass a wonderful arrangement to carry out the complex 
function of a single papilla ; nor must we lose sight of direct sensi- 
tive, motor, and ganglionic fibres given to all parts of the tongue, 
which will help to explain the combined sense of taste and touch 
or roughness ; and the induced action of swallowing when the back 
part of the tongue is irritated or supplied with any object of taste ; 
as well as the rapidity with which the secretions of the mucous 
crypts or follicles may by such be influenced. When we come to 
question why one substance should be bitter, another sweet, — one 
styptic or rough as alum, another soft or bland as gum, — whether 
the solutions of these various bodies excite mechanical, chemical, 
electrical, or thermal impulses, which normally affect the terminal 
plexus after a constant manner, or whether there yet remains an 
impulse of a character which does not belong to the domain of the 
known forces, is a matter of speculative philosophy ; and the more 
difficult becomes the question of the real value of each part or their 
relative functions, when we find that for all substances to produce 
the sensations of taste, it is not necessary they should be directly 
presented to the tongue or the outside of the papillae ; as the taste of 
many can be conveyed by the blood through absorption into the 
system. Possibly some real change of a more or less temporary 
nature is produced in the condition of the sensory nerve ; its statical 
state, so to speak, is disturbed ; sometimes heightened for the recep- 
tion of other impressions ; sometimes rendered incapable of receiving 
them until the former impression is diminished if not entirely 
absent ; and in severe catarrh often rendered indistinguishable ; here 
the secretions may be so changed as to suspend the finer uses of the 
various parts. Indeed, seeing in our own case how much these 
organs are exposed to very hot or very cold bodies, how constantly 
their surfaces are subjected to very rough usage or abrasion under 
mastication of hard food, we may be surprised that the discrimina- 
tion between similar substances should be so delicate ; often to some 
extent aided doubtless by the senses of smell and touch, — in fact we 
could hardly expect the terminal portion of these organs to retain 
their integrity, unless endowed with the power of considerable 
resistance, of rapid reparation, or peculiarly constructed to remain 
in such constant readiness. 
The details of some of the parts cursorily alluded to, are not of 
easy description, from the difficulty of deciding to which part small 
portions may belong when separated from the rest, and from the 
