nd that taste is the result of a concurrent action of the
fifth, ninth, and twelfth pairs of nerves.

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865. What is the chief organ of taste? What other parts participate in
the function? 866-870. _Give the anatomy of the organs of taste._ 866.
Give the structure of the tongue. 867. Is this organ abundantly
supplied with blood? From what source does the tongue derive its
nerves?

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[Illustration: Fig. 134. A view of one side of the neck, showing the
nerves of the tongue. 1, A fragment of the temporal bone. 2, 3, 4, 6, 7,
8, 9, 10, 11, 12, Muscles of the tongue, fauces, and neck. 5, The tongue.
13, The common carotid artery. 14, The jugular vein. 15, The external
carotid. 16, The internal carotid. 17, The gustatory branch of the fifth
pair of nerves. 20, The glosso-pharyngeal nerve. 21, The hypo-glossal, or
the muscular nerve of the tongue. 24, The pneumogastric nerve. 25, The
facial nerve.]

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868. What is the appearance of the surface of the tongue? Explain fig.
134.

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868. The surface of the tongue is thickly studded with fine papillae,
or _vil'li_, which give the organ a velvety appearance. These papillae
are of three varieties. The first is situated near the base of the
tongue. They belong to the class of mucous follicles. They are larger
than the others, and are called _len-tic'u-lar_, from being shaped
like a lens. These, together with the tonsils, (sometimes called the
almonds of the ears,) secrete mucus, to lubricate the food in the act
of deglutition.

869. The instruments of taste are the two other sets of papillae. One
set consists of small, oval-shaped bodies, which are scattered over
the whole surface of the tongue. They give it a rough appearance, and
are called the _fil'i-form_ papillae.

870. The other set of papillae is called the _fun'gi-form_. They are
larger than the former, and consist of small, rounded heads, supported
on short stalks, something in the shape of mushrooms, from which they
derive their name. In the last two described sets of sensitive
papillae, the gustatory branch of the fifth pair of nerves ramifies.

_Observation._ By applying strong acids, as vinegar, to the tongue,
with a hair pencil, these points will become curiously lengthened.

PHYSIOLOGY OF THE ORGANS OF TASTE.

871. TASTE is the sense which makes us acquainted with the savor of
substances. Wh