a quantitative addition of internal glandular tendencies in the
germplasm, or a more complex rearrangement dependent upon reactions
between all the internal secretions?

The term endocrine dominants brings up the inquiries of Mendelism, and
the relation of Mendelian conceptions of dominant and recessive to the
internal secretions. The Mendelians have emphasized the role of the
unit factor in heredity, and the conservation of the unit factor as
an entity through all the adventures of matings. Also, that when unit
factors, say of the color of the eyes, come into conflict, brown or
black being mixed with blue or grey, one, the recessive, is submerged
and overlaid but not destroyed by the other, the dominant. So brown or
black eyes, dark hair, curly hair, dark skin, and so on, are dominant,
while blue or grey eyes, light or straight hair, light skin are
recessives. A nervous temperament is dominant to the phlegmatic. A
number of psychic qualities have been declared to be Mendelian unit
factors: memory, mechanical instinct, mathematical ability, literary
ability, musical ability, and even handwriting.

As architects of human qualities the endocrines must be involved
in the Mendelian unit factors. Moreover, they seem to act upon a
particular locale in different degrees, which is the strongest
argument against the resolution of a number of structural traits into
Mendelian unit characters. Most characters, somatic or psychic, are
the products not of the action of one internal secretion alone, but of
the interlinked activities of all of them. The amount of fat deposited
under the skin, for instance, is influenced by the pituitary, the
thyroid, the pancreas, the liver, the adrenals and the sex glands.
Other qualities, likewise, are resultants of a compromise between all
the endocrine factors comprising the equation of the individual. If
we are to look for unit factors at all in endocrine heredity, we must
look more deeply into constitution, and measure the hormone potentials
and their mobilization or suppression.

It will, in all probability, be found that the stability or
instability of an endocrine will have a good deal to do with the part
played by it in inheritance as well as in the life of the individual
An unstable pituitocentric marrying another unstable pituitocentric
will have children either exceptionally small or tall, or abnormally
bright or stupid. The instability tends to right itself in the next
generation, or