Page 61 - My FlipBook

EXCITING CAUSES OF CARIES. 57 ; : ;

for exploration—a field outside of the province of
this work. The sources of these, however, are sev-
eral : as, vitiated secretions of the mouth ; the saliva,
and the mucus ; abnormal secretion from the stomach
decomposition of animal and vegetable substances in
the mouth ; acids taken with food, or administered as
medicines ; and galvanic action.
The natural state of the mucus is acid, but that of

the saliva alkaline ; so that these secretions counter-
act each other ; but when the saliva and the mucus
are both acid, the teeth must suffer. These secre-
tions may become vitiated, through inability of the
glands, from disease or an enfeebled condition, per-
fectly to perform their functions ; or the blood may
be in an abnormal state, and the glands unable, on

that account, though they were healthy, as they
seldom are in such case, to elaborate healthy saliva
when the fountain is corrupt, the stream cannot be
pure. Thus, anything that produces a diseased con-
dition of the blood, tends to the decay of the teeth
and such diseased condition often has a direct injurious
effect on the secretive apparatus, and so works a
double harm.
But to the theory of the pernicious influence of the
saliva, it may be objected, that, if it were true, all

parts of the teeth would be alike affected. This
objection, however, will loose its force when it is con-