Page 54 - My FlipBook

28 THE MICRO-ORGANISMS OF THE HUMAN MOUTH.

kind of bacterium, but more especially upon simultaneously
occurring i^rocesses which have little or nothing whatever to do
with the decomposition of tlie decaying substance. If, for instance,
a tooth-pulp decomposes in a closed root-canal, an incredible
amount of bad-smelling gas may be formed, so that on opening
the pulp-chamber the whole room will be impregnated with the
odor. But if a tooth-pulp is allowed to decompose in the open
air, hardly any disagreeable smell will be noticed, although the
decomposition of the nutrient medium caused by the fungi may
be identical in both cases. In the latter case, under free access
of air, those products of putrefaction which are accountable for
the offensive odor are further decomposed (oxidized) hy the
oxygen of the air, which is activated by the hydrogen liberated
during the process of decomposition ; the}' consequently do not
manifest their presence at all, AVhere, however, the access of
air is limited, or the air altogether excluded, the oxidation of
these products cannot take place and they escape unchanged
from the solution. The products of fermentation remain the
same in both cases, but their subsequent fate is different.
A solution of white of egg, infected with saliva and kept at
blood temperature, soon gives rise to a stinking smell and an
alkaline reaction (NH3 and SII2). But upon addition of about
2 per cent, of cane-sugar to a similarly infected solution, no bad
smell will be detected ; free NH3 and SH, are not evolved ; the
reaction is acid. iSTevertheless, we have no reason to doubt that
the white of egg undergoes the same decomposition in both cases.
The products arising from the decomposition of these albu-
minous substances are very numerous. According to Fliigge,^
they are: carbonic acid, hydrogen, free nitrogen, sulphuretted
hydrogen, phosplmretted hydrogen, marsh gas, formic, acetic,
butyric, valeric, palmitic, acrylic, crotonic, glycolic, lactic, and
yalerolactanic acids; oxalic and succinic acids, leucine, glycocoll,
glutaminic, asparaginic, and amidostearinic acids; ammonia,
carbonate of ammonia, sulphide of ammonia; numerous amine
bases, propylamine, trimethylamine, etc.; indol, scatol, scatol-
carbonic acid ; tyrosine and its derivatives of the aromatic series,
and lastly the ptomaines.
The large number of acids included in this list does not by