Page 258 - My FlipBook

230 THE MICRO-ORQANISMS OF THE HUMAN MOUTH.

For cleansing root-canals, cavities, etc., the more powerful anti-
septics are of course preferable.
Wintergreen oil and similar aromatic substances, which usu-
ally form an important constituent of mouth-washes, have as far
as I have examined them, in an adaptable concentration, very
little antiseptic action, unless the oil of peppermint is an excep-
tion. This possesses considerable antiseptic action, and is conse-
quently as a constituent of mouth-washes to be preferred to the
other ethereal oils. According to Black,^^^ however, oil of cassia,
oil of cinnamon, and oil of cloves have a much higher antiseptic
action than the oil of peppermint. The results obtained by
Black, in so far as they refer to the oil of cloves and oil of pep-
permint, are in direct contradiction to those obtained by Koch,
who found that the oil of peppermint has an action nearl}' seven
times as strong as that of the oil of cloves. This difference is
no doubt to l)e accounted for in the difference of the bacteria
experimented upon.
If we compare the two tables last given, we find some appa-
rent contradictions. For example, listerine, which is, accord-
ing to one table, forty times weaker than a 10 percent, solution
of the peroxide of hydrogen, devitalizes bacteria much more
quickly than the latter. I am able to explain this remarkable
difference only on the supposition that the rapidity with which
an antiseptic acts need by no means be proportional to its
strength. We must furthermore distinguish clearly between
those substances which only prevent developmmt, as indicated in
the first three tables, and those which devitalize, as indicated in
the last tal)le. It is possible that an agent may prevent the
development of bacteria in very dilute solutions, and yet not
devitalize them even in more concentrated condition.
In the third place, it may be readily conceived that a highly dif-
fusible substance may penetrate the cell-membrane more quickly
and therefore act more rapidly than a less diffusible one, even
though the latter may retard or prevent development in a much
more dilute condition.
Recently I have tested salol, aseptine, and the acetate of alu-
minium in a similar manner. Salol is a very agreeable antiseptic,
but in my experiments it showed very little action.