Page 94 - My FlipBook

CHAPTER IV.

BIOLOGICAL STUDIES ON THE BACTERIA OF THE MOUTH.

If we compare the life-conditions of bacteria as described in
Chapter I. with the conditions prevailing in the hnman month,
it becomes evident that the oral cavity must be an excellent
breeding-place for these organisms. It is equally clear that both
their number and variety are continually being augmented l)y new
germs which enter with the air, food, and drink. In the course
of a few years hundreds of kinds of bacteria would therefore
become established in the mouth, if the majority of them did
not perish, sooner or later, in the struggle for existence. Any
one, therefore, who continues the search for oral bacteria, by
means of the modern culture-methods, for a long period of time^
will continually meet with new kinds, until at last all cultivable
micro-organisms, whose germs occur in the air, in food and
drink, will have been found in the oral cavity. Within the
last few years I have isolated more than one hundred dift'erent
kinds of bacteria from the juices and deposits in the mouth.
A number of these were identical witli well-known and widely
distributed species (for examyde, hay bacillus, potato bacillus,
lactic acid bacillus, bacillus of green pus. Micrococcus tetragenus,
Mycoderma aceti. Staphylococcus pyogenes aureus and albus,
etc.), while others appeared to be new kinds, although I was not
able, on account of the great number, to attempt in every case to
establish the identity or non-identity with known species.
It -must be supposed that the occurrence of many of these
bacteria in the mouth was purely accidental, that they had
entered the oral cavity but shortly before the examination was
made, and disappeared again soon after. Some years ago, I found
68