5.  Combinations of these, as well as of other glands—­with joint predominance—­occur and indeed form the majority of populations.  The phenomena of varieties in species are thus explained.

6.  Internal secretion traits are inherited, and variations in heredity are essentially the structural representation of the resultant of a parallelogram of forces exerted by each of the parental prepotent glands.  If they are of the same type, they may reinforce each other:  if not, inhibitions and compensations will come into play.  Mendelian laws may apply.

7.  The process of evolution, as the play of natural selection upon these variations, becomes comprehensible from a new standpoint.

8.  Certain diseases, and disease tendencies, both acute and constitutional, as well as traits of temperament and character, and predetermined reactions to certain recurring situations in life, are rooted in the glandular soils that compose the stuff of the individual.

9.  The subconscious, of which the vegetative apparatus is the physical basis, leads back to the internal secretions for the profoundest springs of its secrets.  We shall see how and why.

10.  Given the internal secretory composition, so to speak, of an individual—­his endocrine formula—­and so his intravisceral pressures, one may predict, within limits, his physical and psychic make-up, the general lines of his life, diseases, tastes, idiosyncrasies and habits.

11.  Within limits, if the previous history of an individual is known, his physical appearance may be approximately described, and his future outlined.

12.  Conversely, given the physical and psychic composition of an individual, and his past history, one may deduce the internal secretion type to which he belongs.

Examples: 

  A. One Thyroid-centered Type has
    Bright eyes
    Good clean teeth
    Symmetrical features
    Moist flushed skin
    Temperamental attitude toward life
    Tendency to heart, intestinal and nervous disease

  B. One Pituitary-centered Type
    Abnormally large or small size
    Musical—­acute sense of rhythm
    Asymmetrical features
    Tendency to cyclic or periodic diseases

  C. One Adrenal-centered Type
    Hairy
    Dark
    Masculinity marked
    Tendency to diphtheria and hernia

These are some of the master types.  They have their variants depending upon the influences of the other glands, especially the interstitial cells of the sex glands.

ANTE-NATAL DEVELOPMENT

In their ensemble, the glands of internal secretion wield a determining influence upon the development of the individual from his very inception.  If his various powers may be conceived of as an orchestra, they may be said to conduct it from the very beginning of its movements, and to cease only with its termination.  From the moment when the spermatozoon penetrates and fecundates the ovum, the fate of the future being is settled by their disposition.  The seal of his destiny is soaked with their substance.