Page 158 - My FlipBook

132 THE MICRO-ORGANISMS OF THE HUMAN MOUTH.

action of almost any acid to produce cavities especially in eDamel,
since by the decalcification the entire tissue of the enamel is de-
stroyed. Moreover, when the experiment is made in the air,
more or less discoloration appears. By such experiments, how-
ever, nothing more is proved than the universall}^ recognized
fact that acids exert a decalcifying effect on dental tissue. The
identity of a destructive process in the tooth with decay itself
can be established by the microscope only.
But the untenableness of the purely chemical theory of decay
has been so strikingly and repeatedly demonstrated within the
last few years that it seems unnecessary to enter upon a closer
consideration of the subject here.

Parasitic Theory of Dental Decay.
It is not quite certain who was the first to accuse micro-organ-
isms of being concerned in the production of tooth-decay. The
credit of having originated this view is generally given to the
Dresden physician, Ficinus.^^ Prof. Erdl,^^ however, seems to have
been two years in advance of Ficinus. Erdl regards the " caries
materie" as parasites. This on its first appearance forms upon
the crown a delicate, colorless membrane composed of cells ; later
these cells become more irregular and their nuclei more distinct.
But since Erdl employed muriatic acid to isolate his " caries
matter," it is quite probable that the delicate membrane which
he obtained was nothing else than ISTasmyth's membrane. In
order to destroy these parasites and thereby hinder the progress
of the decay, Erdl recommends creasote and nitric acid. He
first applies creasote until the " caries matter" is impregnated
with it, then nitric acid, which immediately produces violent and
complete decomposition of the creasote, as well as of the parasites
saturated with it.
Ficinus^^ attributes decay to the action of his " denticolse."
These proliferate in the enamel-cuticle, which they decompose;
they then attack the enamel, destroy the connection between the
enamel-prisms, and thus penetrate to the dentine, which they
cause to decay in the same manner.
Klencke^*^ also describes a parasite, Protococcus dentalis, dis-