Page 250 - My FlipBook

222 THE MICRO-ORQANISMS OF THE HUMAN MOUTH.

The immunity of these races cannot, it seems to me, be ex-
plained by the favorable hygienic mode of life, climatic influ-
ences, etc., alone. They often suffer from famines ; various dis-
eases are frequent, especially among the Lapps, and the latter,
as well as the Esquimaux, are becoming extinct. That the
number of inhabitants of Iceland has remained stationary for
the last few centuries is said to be due to " volcanic eruptions,
frequent epidemics, unhealthy mode of life, famines, etc."
I think therefore every one will agree with me that the con-
ditions prevailing in the countries named are not to be regarded
as conducive to a perfect development of the human body.
Those factors which contribute to restrict the occurrence of
decay of the teeth are, in my opinion, (1) a mode of life favor-
able to the development of the whole body, (2) the use of food
which is suificiently hard to afford the teeth the exercise neces-
sary for their vigorous development, (3) the use of food which
does not undergo an acid fermentation in the mouth.