e temperature of the skin is being raised, and of cold
when it is being lowered. This explains why in going into a hallway from a
heated room one receives a sensation of cold, while in coming into the
same hallway from the outside air he receives a sensation of warmth. It is
for the same reason that we are able to distinguish only the relative, not
the actual, temperature of bodies.

*Muscular Sensations.*--These are sensations produced by impulses arising
at the muscles. Such impulses originate at the fiber terminations which
are found in both the muscles and their tendons. By muscular sensations
one is conscious of the location of a contracting muscle and of the degree
of its tension. They also make it possible to judge of the weight of
objects.

[Fig. 146]

Fig. 146--*Sense organs of taste.* _A._ Map of upper surface of tongue,
showing on the left the different kinds of papillae, and on the right the
areas of taste (after Hall). Area sensitive to bitter (----); to acid
(....); to salt (--.--.--.--); to sweet (--------). _B._ Section through a
papilla. _n._ Small nerve connecting with taste buds at _d. e._
Epithelium. _C._ Single taste bud magnified. _n._ Nerve, the fibers of
which terminate between the spindle-shaped cells _a. e._ Epithelial cells.

*The Sensation of Taste.*--The sense organs of taste are found chiefly in
the mucous membrane covering the upper surface of the tongue. Scattered
over this surface are a number of rounded elevations, or large papillae (A,
Fig. 146). Toward the back of the tongue two rows of these, larger than
the others, converge to meet at an angle, where is located a papilla of
exceptional size. Surrounding each papilla is a narrow depression, within
which are found the sense organs of taste (B, Fig. 146). These are called,
from their shape, _taste buds_, and each bud contains a central cavity
which communicates with the surface by a small opening--_the gustatory
pore_. Within this cavity are many slender, spindle-shaped cells which
terminate in hair-like projections at the end nearest the pore, but in
short fibers at the other end. Nerve fibers enter at the inner ends of the
buds and spread out between the cells (_C_, Fig. 146). These fibers pass
to the brain as parts of two pairs of nerves--those from the front of the
tongue joining the trigeminal nerve, and those from the back of the
tongue, the glossopharyngeal nerve.

The gus