ed for a time. In some cases
quinine may produce temporary deafness.

The practice of snuffing up cold water into the nostrils is occasionally
followed by an acute inflammation of the middle ear, some of the water
finding its way through the Eustachian tube into this part of the organ of
hearing. The nasal douche, so often advised as a home remedy for nasal
catarrh, should be used only with great caution, and always in accordance
with detailed directions from a physician.

348. Effect of Tobacco upon the Hearing. The sense of hearing is
often injured by the use of tobacco. The irritating smoke filling all the
inner cavity of the mouth and throat, readily finds its way up the
Eustachian tube, dries the membrane, and irritates or inflames the
delicate mechanism of the inner ear. Thus may be produced a variety of
serious aural disturbances, such as unnatural noises, whistling, and
roaring, followed oftentimes by a partial loss of hearing.

Hearing may be impaired by the use of alcoholic beverages. Alcohol
inflames the mucous membrane of the throat, then by its nearness the
lining of the Eustachian tube, and finally may injure the delicate
apparatus of the internal ear.

Additional Experiments.

Experiment 162. Use a small pair of wooden compasses, or an
ordinary pair of dividers with their points guarded by a small piece of
cork. Apply the points of the compasses lightly and simultaneously to
different parts of the body, and ascertain at what distance apart the
points are felt as two. The following is the order of sensibility: tip
of tongue, tip of the middle finger, palm, forehead, and back of hand.

Experiment 163. Test as in preceding experiment the skin of the
arm, beginning at the shoulder and passing downwards. Observe that the
sensibility is greater as one tests towards the fingers, and also in the
transverse than in the long axis of the limb. In all cases compare the
results obtained on both sides of the body.

Experiment 164. By means of a spray-producer, spray the back of the
hand with ether, and observe how the sensibility is abolished.

Experiment 165. Touch your forehead with your forefinger; the
finger appears to feel the contact, but on rubbing the forefinger
rapidly over the forehead, it is the latter which is interpreted as
"feeling" the finger.

Experiment 166. Generally speaking, the sensation of touch is
referred to the cutaneous surfaces. In certain c