nx included, is lined with a
_mucous membrane_, which is continuous with that covering the inner
surface of the digestive organs. That is to say, the nose, the mouth,
the back of the throat, the larynx, the windpipe, the bronchial tubes,
the gullet, the stomach and intestines are all brought into structural
connection by this common lining membrane. Moreover, these parts have
to some extent the same nerve supply, and are, in fact, so related
that derangement in one region must affect sooner or later, and to a
variable degree according to the resisting power of each individual,
other related parts. Thus it is that a disordered stomach affects the
voice, that a cold may affect digestion, that a catarrh of the nose
will eventually reach the vocal bands, etc.

Another principle of wide-reaching importance is that all sorts of
_compression_ must, of necessity, be attended by functional disorders,
which, if long continued, will result in organic or structural changes
implying deterioration of a kind that must be more or less permanent.
Whatever the cause of compression of the chest or neck, the result is
the same: a retention of blood in parts for too long a period--a
condition of things which must inevitably be injurious.

The tissues are made up of cells, which are the individuals of the
bodily community. Around these cells are found the smallest of the
blood-vessels, the capillaries, between which and the tissues a sort
of physiological barter is continually going on, the capillaries
handing over oxygen and food supplies from the blood, and receiving
waste materials in return, as the blood creeps along at a very slow
rate. If, however, in consequence of pressure on a part, the blood be
kept back in these minute vessels too long, there is naturally a
double evil: first, the food and oxygen supplies fail--they have been
used up already--and, secondly, the waste products accumulate in the
tissue cells, so that there is a combination of starvation and
poisoning--a sort of physiological slum life, with corresponding
degradation; so that it is not at all difficult to understand why
tight collars, neckbands, corsets, etc., must be unmixed evils, apart
altogether from the fact that they so greatly hamper the very
movements the voice-user most requires for the successful execution of
his task.

All sorts of straining or forcing also involve this same evil, known
to medical men as _congestion_. The sore throats so common with tho