Page 765 - My FlipBook

MOBBID CONDITIONS OF THE FLUIDS OF THE MOUTH. 775
<;aries exerted by the morbid conditions of the saliva must be subordi-
nate or secondary, in that they furnish a better soil for the promotion
of fermentation or assist in decomposition by virtue of the acid they
may contain. The iirst of these inflnences has been considered under
the head of Heredity. That the fluids of the mouth often contain acids
in a very dilute form, but sufficient in amount to be readily detected by
litmus-paper, is well known to all who have given attention to the sub-
ject. This acid, whatever its origin, is distributed generally in the
fluids. There is no localization demonstrable by our present modes of
research, except it be that the mucus exuded from the gum in a state
of irritation is more markedly acid than the other fluids. This latter
point, as it affects only special cases, will be examined later.
Some years ago very extended examinations of the fluids of the
mouth were made with reference to acidity and its possible connec-
tion with caries. I made personal tests in several thousand cases.
These gave rather complex results, but in the main seemed to demon-
strate that the two conditions were in no wise connected as cause
tind effect. So decided was this that, while I went into the series of
observations with a conviction that Tomes, Magitot, and others were
right in attributing caries to this cause, I retired with the belief that,
whatever be the cause of caries, it has little or no connection with
acid saliva. In many the tendency to caries was not in any degree
related to the degree of acidity of the fluids of the mouth. In an article
which I wrote in 1880, after this series of experiments, these sentences
occur: "Decay of the teeth is certainly a specific disease, running a
specific course, and evidently arising from a specific cause, but this
<^ause is not as yet certainly known." . . . . " While there is no decay
without the presence of an acid, there is not necessarily decay because
of the presence of an acid." . . . . " While an acid is not only always
present, but is probably a neeessity to the inception and progress of
•decay, there may be an agent acting in conjunction with the acid that
is not yet known or recognized."
Now, after the demonstration of the cause of caries by Dr. Miller,
which represents the unknoicn in these sentences, ^ve are able to analyze
the probable effects of morbid conditions of the fluids of the mouth more
olosely than before, especially after studying the microscopic phenomena
in the light thrown upon them by the demonstration of the cause. It
is now perfectly clear that acids alone, while they may decalcify the
teeth, cannot produce the phenomena of caries. Dr. Mayr has well
said: "The decay under consideration is so specific that the mere action
of acids is not sufficient to produce it."^ The occurrence of micro-
organisms in, and the widening of the calibre of, the tubules is a prom-
inent manifestation without which the presence of caries, no matter
what the amount of softening, may confidently be denied. This has
now been confirmed by so many observers that it has become a truism
;
and after the studies of the physiology of this fungus cited in the pre-
vious pages we have no need to go to the fluids of the mouth to find
the acid. It is developed in situ. Acids that are commingled with the
fluids of the mouth, whether developed therein or introduced from with-
^ Independent Practitioner, 1884, p. 195.