y will permit the
eruption of the teeth within the normal time limits, both the milk
teeth and the permanent teeth. When there is equilibrium between the
pituitary and the gonads, the teeth will be regular in shape and
position. Carious teeth, in children and adults, sometimes indicate
endocrine imbalance. Thyroid and adrenal balance determines the
resistance to decay of the molars. Early decay of the molars in
children is significant of insufficiency of the thyroid. When the
first permanent molar, which should appear in the upper arch in its
usual position between the sixth or eighth years, does not, there has
been a prenatal disturbance of the pituitary, according to Chayes
and others. Rapid decay of the teeth in childhood should always call
attention to the parathyroids.

In pregnancy, the teeth suffer particularly because of disturbances of
the endocrines. The saying, "A tooth for every child," is said to have
its equivalent in every language. The bicuspids and second permanent
molars erupt around puberty, when profound readjustments are going on
among the glands of internal secretion. They consequently suffer with
their abnormalities or divergences from type. The teeth thus furnish a
good deal of information concerning the distribution of the balance of
power among the hormones.

THE SKIN

The skin is influenced in its color, moisture, hairiness, texture, fat
content and disease vulnerability by the endocrines. The question of
color is very interesting, for it is probably the expression of the
blending action of the different internal secretions. Davenport, the
American student of heredity and eugenics, has shown that neither
white nor black skins are either perfectly white or perfectly black,
but are mixtures in various proportions of black, yellow, red and
white. The exact percentages of the pigments in each particular skin,
can be determined by means of a rotating disc. Thus a white person's
skin may have the following composition:

Black 8% Red 50%

Yellow 9% White 33%

The composition of the skin of a very black negro may be:

Black 68% Red 26%

Yellow 2% White 7%

Now the fact that in Addison's disease in which the adrenals are
destroyed there occurs a coincident increase in the black in the
skin, and other evidence pointing to adrenal implication in dark
complexioned white people, as well as in those possessing pigmented
spots, seems to indicate the adrenals as controllers of the black
and whit