396 PAPILLA OP TONGUE :—NATURE OF SENSE OF TASTE. 
cleans of all its flesh the bone he licks, and that the Lion, by 
a single stroke of his tongue, can take off the skin from any 
part of the Human body. The tongue itself is made-up of 
muscular substance, which accomplishes the varied move¬ 
ments that are required in the acts of mastication and in the 
production of articulate sounds. It is supplied with nerves 
from the third division of the fifth pair, from the glosso¬ 
pharyngeal, and from the hypoglossal (§ 459). The last is 
the motor nerve of the tongue; the first is the one chiefly 
concerned in the conveyance of sensory impressions from the 
front and sides of the tongue; and the other (the glosso¬ 
pharyngeal) seems to have for its office to convey those im¬ 
pressions from the back of the tongue which excite the muscles 
of swallowing to action (§ 470), as well as those which produce 
the sensation of nausea and excite the act of vomiting. The 
gustative papillae, which have a very thin epithelial covering, 
are for the most part supplied from the fifth pair; and the 
branch of this proceeding to the tongue is known as the 
lingual nerve. When they are called into action by the con¬ 
tact of substances having a pleasant savour, they not unfre- 
quently become very turgid, and rise-up from the surface of 
the mucous membrane; in this manner is produced the rough¬ 
ness that is felt on the surface of any portion of the tongue or 
inside of the cheek, against which a piece of barley-sugar or 
other similar substance has lain for some little time. 
501. A considerable part of the impression produced by 
many substances, is received through the sense of Smell rather 
than by that of Taste. Of 4his any one may convince him¬ 
self by closing the nostrils and breathing through the mouth 
only, whilst holding in the mouth, or even rubbing between 
the tongue and the palate, some aromatic substance ; its taste 
is then scarcely recognised, although it is immediately per¬ 
ceived when the nasal passages are re-opened, and its effluvia 
are drawn into them. There are many substances, however, 
whose taste, though not in the least dependent upon the 
action of the nose, is nevertheless of a powerful character; 
such are sugar, salt, quinine, and vinegar. Others, again, 
by irritating the mucous membrane, produce a sense of pun¬ 
gency allied to that which the same substances (strong acids, 
for instance, pepper, or mustard) will produce when applied 
to the skin for a sufficient length of time. Such sensations, 
