Page 258 - My FlipBook

130 PATHOLOGY OF THE HARD TISSUES OF THE TEETH.
In this, Dr. Michaels claims to have found the means of
determining definitely the existence of the conditions of suscep-
tibility to, or immunity from, dental caries, by the examination
of a few drops of the individual's saliva. Persons who have
spent some time in Dr. Michaels' laboratory and looked over his
work, seem convinced that he can do what he asserts. In this
writing, the qualities of the saliva are summarized thus: (1)
Normal, (2) Hypo-acid, (3) Hyper-acid, and (4) Cacochymic.
In the first, the normal, little or no caries occurs. In the
hypo-acid condition, the susceptibility is intense or moderate,
according to the intensity of the condition. In the hyper-acid
condition there is immunity from dental caries. The cacochymic
denotes a bad condition of the saliva, due to some functional
derangement or organic disease without further specification, and
includes very variable conditions. It has no special reference
to dental caries.
The terms, hypo-acid and hyper-acid diathetic states, do not
refer to reactions to litmus. He says: "The abnormal vital
processes tend in mankind to pathological conditions, which we
may classify under two humoral conditions, viz., hypo-acidity
and hyper-acidity. The first state (lymphatism) is the expres-
sion of a vital over-activity and has as consequences the con-
tagious diathesis (scrofula, tuberculosis, syphilis). The oxida-
tions are over-active and the hydrations superior to the normal,
hence there is a decrease in organic acidity and an increase in
the saline chlorids excreted by the economy. Hypo-acidity,
according to Duclaux, favors chemical changes in the tissues.
In the hypo-acid diathesis all of the oxidations are exaggerated
and above normal. . . . Hyper-acidity is a particular state
of the organism characterized in a general way by slowness in
the biochemical changes. ... It is not doubtful that the
activity of caries in some individuals and the immunity from or
the slowness of decay in others are in correlation with diathetic
states well determined, resulting from a lack of proper balance
of the general factors, and in particular of the blood plasma."
Many of the expressions in this brochure seem difficult for
many who have read them to understand, but it has seemed evi-
dent that, while many other substances in the saliva are found to
influence conditions as to caries of the teeth, the absence or pres-
ence of the sulphocyanids, or the large or small proportions
present, is the most constant mark separating the condition of
susceptibility to caries from the condition of immunity.
Much of the work is done by the examination of crystals by