usually bring general sensations; the spinal and cranial nerves usually bring special sensations.
Examples of general sensations are hunger, thirst, satiety, nausea, faintness, giddiness, fatigue, weight, aching, shuddering, restlessness, blues, creepy feeling, tingling, sleepiness, pain, illness. Any nerve can convey the general sensation of pain, if injured along its course. If a nerve of touch is cut, there is no sensation of touch, but of pain. Touch sensations come only from the ends of the nerves. General sensations are of many kinds. We are only half conscious of some of them; many of them are hard even to describe.
Hygiene of the General Sensations.—General sensation is an invaluable aid to the health. Without it as a guide, the body could not remain alive a single day. Pain should be heeded as our best friend, and not killed with poisonous drugs as if it were our worst enemy. We should not deaden the stomach ache with an after-dinner cigar. If we do not go to bed when sleepy, the desire for sleep may leave us, and we will undergo untold suffering from sleeplessness. Thirst should be satisfied with cool water, which quenches it the best; he who makes his teeth ache with ice water will inflame his stomach and be continually thirsty. He who does not stop eating when his hunger is satisfied, will distend his stomach with food, and the stretched organ will be harder to satisfy thereafter; in fact, eating after a feeling of satiety may cause indigestion so that the cells will not get the food. A dyspeptic is always hungry, for the cells are starving. Fatigue of body or mind gives us wise counsel; but this feeling may be deadened by alcohol or tobacco, and work continued until the body is injured. We should heed the warning of pain or fatigue or restlessness as promptly as an engineer heeds a red flag on the railway track. One who uses narcotics acts like a reckless engineer who removes the danger signal and goes ahead, hoping by good luck to escape an accident.
Most of the nerves of touch end in papillæ of the dermis
as microscopic, egg-shaped bodies (Fig. 120). There are
also many in the interior of the mouth, especially on the
tongue. On the palms they are arranged in curved lines,
and on the tips of the fingers they are in circular lines,
with one papilla in the center. The delicacy of the sense
of touch varies very much in different parts of the skin.
This delicacy refers to two things: the ability to feel the
slightest pressure and the ability to tell the exact point of
