Science likewise illuminates the whole problem of genius.  Hidden in the common stuff of humanity lies buried this power of self-expression.  Modern science is teaching us that genius is not some mysterious gift of the gods, some treasure conferred upon individuals chosen by chance.  Nor is it, as Lombroso believed, the result of a pathological and degenerate condition, allied to criminality and madness.  Rather is it due to the removal of physiological and psychological inhibitions and constraints which makes possible the release and the channeling of the primordial inner energies of man into full and divine expression.  The removal of these inhibitions, so scientists assure us, makes possible more rapid and profound perceptions,—­so rapid indeed that they seem to the ordinary human being, practically instantaneous, or intuitive.  The qualities of genius are not, therefore, qualities lacking in the common reservoir of humanity, but rather the unimpeded release and direction of powers latent in all of us.  This process of course is not necessarily conscious.

This view is substantiated by the opposite problem of feeble-mindedness.  Recent researches throw a new light on this problem and the contrasting one of human genius.  Mental defect and feeble-mindedness are conceived essentially as retardation, arrest of development, differing in degree so that the victim is either an idiot, an imbecile, feeble-minded or a moron, according to the relative period at which mental development ceases.

Scientific research into the functioning of the ductless glands and their secretions throws a new light on this problem.  Not long ago these glands were a complete enigma, owing to the fact that they are not provided with excretory ducts.  It has just recently been shown that these organs, such as the thyroid, the pituitary, the suprarenal, the parathyroid and the reproductive glands, exercise an all-powerful influence upon the course of individual development or deficiency.  Gley, to whom we owe much of our knowledge of glandular action, has asserted that “the genesis and exercise of the higher faculties of men are conditioned by the purely chemical action of the product of these secretions.  Let psychologists consider these facts.”

These internal secretions or endocrines pass directly into the blood stream, and exercise a dominating power over health and personality.  Deficiency in the thyroid secretion, especially during the years of infancy and early childhood, creates disorders of nutrition and inactivity of the nervous system.  The particular form of idiocy known as cretinism is the result of this deficiency, which produces an arrest of the development of the brain cells.  The other glands and their secretions likewise exercise the most profound influence upon development, growth and assimilation.  Most of these glands are of very small size, none of them larger than a walnut, and some—­the parathyroids—­almost microscopic.  Nevertheless, they are essential to the proper maintenance of life in the body, and no less organically related to mental and psychic development as well.