to produce
in this sensitive membrane a diseased condition similar to that existing
in the air-passages of the head. The throat may feel dry, husky, and at
times slightly sore or raw; or, from the muco-purulent discharge that is
almost constantly dropping down over its surface, the patient may feel
very little inconvenience from the disease of the throat until it is far
advanced--the moistening and lubricating effect of the matter that drops
on the surface tending to blunt the sensibility of the parts. (_See
pharyngitis for symptoms and treatment_.)

THE EXTENSION OF THE DISEASE TO THE LARYNX. The larynx, situated
directly below the pharynx (throat), is subjected to the influence of
the same irritation from acrid and poisonous discharges dropping into
the throat from the head. More or less of it is removed by hawking and
spitting, but some remains and is drawn into the larynx, or still lower
into the trachea (windpipe), with the inspired air. Thus the disease
creeps along the continuous mucous surfaces of the air-passages, the
acrid poisonous discharge arousing in its track the irritation,
inflammation, ulceration, and thickening of the lining membrane which
characterize the disease in other portions of the air-passages. The
symptoms and treatment of laryngitis will be found under its appropriate
classification.

BRONCHITIS AND CONSUMPTION. We have already detailed the manner in which
the throat, larynx, and trachea, in succession, become affected from
catarrh, or ozaena. By the same process of extension, the bronchial
tubes, and lastly, the _parenchyma_, or substance of the lungs, in their
turn, become diseased, and bronchitis and consumption are firmly
established. Tightness in the chest, with difficulty of breathing;
soreness; darting, sharp, or dull, heavy pain, or a prickly, distressing
sensation, accompanied with more or less cough and expectoration--are
evidences that the bronchial tubes have become affected, and they should
admonish the sufferer _that he is now standing on the stepping-stone to_
CONSUMPTION, over which thousands annually tread, in their slow journey
to the grave.

[Illustration: Fig. 8.
Internal and external ear. _1_, External ear.
_2_, Internal auditory meatus. _3_, Tympanum. _4_, Labyrinth.
_5_, Eustachian tube.]

DEAFNESS. By means of a small canal, called the _eustachian tube_, an
air-passage and communication between the throat and middle ear is
formed. (See Fig. 8.) This passage is l