THE VOICE AND SPEECH. 647 
which the glottic opening can not be sufficiently narrowed, 
allows of undue escape of air, and gives rise to feebleness and 
harshness of the voice. 3. There may be almost complete loss 
of voice from paralysis of both thyro-arytenoid muscles. 4. 
When the crico-thyroid muscles are paralyzed, owing to im- 
perfect tension of the vocal bands, the voice may become lower 
pitched and harsh. Any form of paralysis of the vocal bands 
should arrest attention and lead to a careful examination of the 
chest for aneurism, etc.,and to general inquiry, for even the 
brain may be involved. 
The importance of the muscles, by which the larynx is raised 
and steadied, must not be overlooked. In professional singers 
from constant practice they often become greatly enlarged. 
‘We may here remark upon the value of singing when not 
pushed to the verge of fatigue, when free from straining, and 
in a pure atmosphere, as a healthful exercise, the whole of 
which does not consist in the good arising from the use of the 
chest, larynx, etc., or the additional amount of oxygen respired, 
but also from complicated and ill-understood nervous effects. 
At puberty, in both sexes, the larynx shares in those changes 
of relative and absolute size which the body then experiences 
so generally. The thickening from excess of blood and nerv- 
ous energy produces, especially in youths, a harsh voice, which 
is, in this instance, as in all others, an indication of the need 
of rest of the parts. To sing under such circumstances is, of 
course, liable to induce permanent injury in the form of weak- 
ness or harshness of voice; but once this period is passed, regu- 
lar vocal gymnastics may be of great service in perfecting an 
organ unrivaled as a musical instrument, and by means of 
which man is raised through the endowment of speech vastly 
above all other animals. 
The subject of voice production and voice preservation is 
one of the utmost importance in education, though it receives 
comparatively little attention. The public taste for high- 
pitched vocalization does unquestionably tend to ruin voices, 
and is alike opposed to artistic and physiological principles. 
While a few may reach the prescribed standard of the public 
taste, the many fail in the attempt. 
Comparative.—Much more is known of the sounds emanating 
from the lower animals than of the mechanisms by which they 
are produced. This applies, of course, especially to such sounds 
as are not produced by external parts of the body, it being 
very difficult to investigate these experimentally or to observe 
