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30-4 THE MICRO-ORGANISMS OF THE HUMAN MOUTH.
" Of twenty-five different kinds of bacteria which I have isolated
fi-om the secretions of the human mouth, twelve are cocci and
thirteen bacilli or bacteria. It was not possible in all cases to
make a distinction between bacilli and bacteria, since so many
kinds produce at the same time long rods (bacilli) and short
rods (bacteria).
" Twelve of the mouth-bacteria I found again in the fffices, and
eight in the contents of the stomach. In the latter case the
material for the investigations was furnished by a gentleman
who could evacuate his stomach at will an hour or two after
partaking of a small quantity of fruit, particularly strawberries.
Each time the oral cavity was carefully cleaned and sterilized
with sublimate (1-1000), in order to prevent the intermixture
of bacteria from the mouth. That the micro-organisms really
came from the stomach, and not from the mouth or a'sophagus,
could readily be seen by their large numbers. I have satisfied
mvself by repeated experiments that in plate-cultures fi*om the
saliva of a mouth which has been treated as stated above, very
few, or no colonies at all, will be developed, while in the cultures
from the contents of the stomach a small drop in 5.0 cc. of gela-
tine would produce colonies so numerous that the separate ones
were indistinguishable. Again, all organisms which were repre-
sented by only a few colonies were excluded.
" It is, perhaps, allowable to take for granted that all the
stomach-bacteria enter the stomach along with the food ; it is
much less probable that they find entrance from the duodenum,
although the possibility cannot be entirely excluded. It -would
not be permissible to assume that the intestinal bacteria all came
from the stomach, since an entrance per anum is not to be over-
looked, and since the stomach is supposed to present an impas-
sable barrier for most micro-organisms. The results obtained
from the experiments to be described indicate, however, that
the latter is not the case, but that any bacterium, under a variety
of conditions, may readily pass the stomach without losing its
powej of development. The resistance of many micro-organ-
isms to the action of the gastric juice may be seen from the fol-
lowing experiment
" About three hours after a moderate meal, 70 cc. of the con-
30-4 THE MICRO-ORGANISMS OF THE HUMAN MOUTH.
" Of twenty-five different kinds of bacteria which I have isolated
fi-om the secretions of the human mouth, twelve are cocci and
thirteen bacilli or bacteria. It was not possible in all cases to
make a distinction between bacilli and bacteria, since so many
kinds produce at the same time long rods (bacilli) and short
rods (bacteria).
" Twelve of the mouth-bacteria I found again in the fffices, and
eight in the contents of the stomach. In the latter case the
material for the investigations was furnished by a gentleman
who could evacuate his stomach at will an hour or two after
partaking of a small quantity of fruit, particularly strawberries.
Each time the oral cavity was carefully cleaned and sterilized
with sublimate (1-1000), in order to prevent the intermixture
of bacteria from the mouth. That the micro-organisms really
came from the stomach, and not from the mouth or a'sophagus,
could readily be seen by their large numbers. I have satisfied
mvself by repeated experiments that in plate-cultures fi*om the
saliva of a mouth which has been treated as stated above, very
few, or no colonies at all, will be developed, while in the cultures
from the contents of the stomach a small drop in 5.0 cc. of gela-
tine would produce colonies so numerous that the separate ones
were indistinguishable. Again, all organisms which were repre-
sented by only a few colonies were excluded.
" It is, perhaps, allowable to take for granted that all the
stomach-bacteria enter the stomach along with the food ; it is
much less probable that they find entrance from the duodenum,
although the possibility cannot be entirely excluded. It -would
not be permissible to assume that the intestinal bacteria all came
from the stomach, since an entrance per anum is not to be over-
looked, and since the stomach is supposed to present an impas-
sable barrier for most micro-organisms. The results obtained
from the experiments to be described indicate, however, that
the latter is not the case, but that any bacterium, under a variety
of conditions, may readily pass the stomach without losing its
powej of development. The resistance of many micro-organ-
isms to the action of the gastric juice may be seen from the fol-
lowing experiment
" About three hours after a moderate meal, 70 cc. of the con-
