HOW THE GLANDS INFLUENCE THE MIND
It is impossible to review here in detail all the facts accumulated concerning the influence of the internal secretions upon all the processes of mind, intellectual and emotional. A volume would not suffice for their adequate consideration. Reflexes, instincts, habits, tendencies and emotions are involved in their machinery. The development and normal functioning of the intellect, the pure reason as Kant called it, are controlled by them. Brain, without them in solution, without enough of them in that wonderful solution, the blood, sleeps or remains dormant like the butterfly in the cocoon. The cretin, who has not enough thyroid or no thyroid, is an imbecile because of his deficiency. Supply him with thyroid from outside sources, feed him animal thyroid, be it of the sheep, the pig, or the goat, and behold a miracle! he is restored to the level of at least the relatively normal intelligence.
Acuteness of perception, memory, logical thought, imagination, conception, emotional expression or inhibition and the entire content of consciousness are influenced by the internal secretions. The most ultramicroscopic activities of the molecules and atoms in the highest nerve cells and nerve tissues are dominated. The speed of their chemistry and their associations, and thus the speed of thought, are regulated. Iodine has been shown to increase the electric conductivity of the brain that is, the rate at which electrons will fly through it. The thyroid may then be regarded as manipulating the amount of iodine brought to play upon the brain cells at a particular moment of danger or exaltation. Adrenalin increases the electric conductivity of the brain. Nerve impulses, and with them sensations and ideas, travel faster or flow more quickly through iodinized or adrenalinized brain cells. In dangerous situations we think more rapidly and keenly, for in emergencies the blood floods the brain with extra thyroid and adrenal secretions.
THE BODY-MIND COMPLEX
Mind, still regarded by most of mankind as something distinct and apart from the body, is thus exhibited as but part and parcel of it. A deaf, dumb, and blind animal, deprived of tongue, and olfactory mucous membrane, without sensations from the outside world can grow no mind, in the sense of intelligence. The sense organs of the body mediate the primary mind stuff. Without internal secretions and a vegetative system there could be no soul, in the sense of complex emotion. Nor those combinations of thought and emotion which synthesize attitudes, sentiments and character. The internal secretions and the vegetative system mediate the primary soul stuff. Mind is thus emulsified with body as a matter of cold literal fact. The soul was once a subtlety of metaphysics. Now when mind appears soaked in matter saturated with chemicals like the hormones, therefore woven out of material threads, the independent entity created out of intangible spirit flies like a ghost at dawn.
View the outlook. Mind, the slippery phantom, now becomes controllable for the purposes of everyday life, because we can put our fingers upon, touch, handle and change these material factors, the internal secretions and the vegetative system. Through them we may affect the very quality of the nerve tissue. The future of the race, the future of human nature, depends upon the knowledge to be born of the researches into the vast possibilities of this idea. Man, the Adventurer, the prey of Chance and Luck, will then become, indeed now becomes, the Captain of Fate and Destiny.
It is, of itself, a revolution in the intellect, to conceive of instincts and emotions, suggestibility and contra-suggestibility, initiative and imitation, volitions and inhibitions as chemical matters. In all their relations, mutually reacting effects and defects, excesses and deficiencies, the internal secretions set up psychic echoes and reflections. When morbid and their equilibrium dislocated, we may even have phobias and neuroses.
A man's nature is essentially his endocrine nature. Primarily, when he is born, he represents a particular inherited combination of different glands of internal secretion. They, constituting the inventory of his vital stock in trade, start him in life. Afterwards, food, the routine of his existence, the accidents of experience, education, disease and misfortune, in short, environment, modify him because they modify his ductless glands and his vegetative apparatus, as well as his brain, depressing some parts, and stimulating others, and so rearranging the system. In particular will he be transformed as the gland is affected which is the centre of the system to which the others adapt and accommodate themselves. The inertia of the system is very great, almost absolute, and always tends to return. If he has children, he hands on his constellation of endocrines, in spite of mishaps, not at all or only slightly transformed. Sometimes, however, the experiential transformation has been sufficiently deep, and shaken the very constitution of his germ-plasm. So family dispositions and traits, national and racial temperaments, are propagated, maintained and varied.
THE SEX INSTINCTS
Hormone reactions, as we have seen, initiate the complicated forces, processes and expressions of sex. The dictum of the founder of modern pathology, Virchow, that Woman was in effect an appendix to the ovaries, has long been taken to apply to her psychic traits as well as somatic. Her mind, like her skin, her hair and her pelvis, is a product of the ovarian endocrines. But these determinations are by no means her monopoly. Man is likewise a creation of the chemical wheels within wheels and springs within springs that are his glands of internal secretion. That he is not so obviously an appendix to his testes is due to two reasons. First, the male sex hormones have not the instability nor cyclic rhythmicity of the female. Secondly, and perhaps consequently, his sex instincts have become overlayered with other more labile instincts, with habits and customs and necessities that appear to oust the sex instinct into an altogether decentralized position. Moreover, it is the function of the female to be the excitor in the sex process: her subconscious, thoroughly aware of the fact, sees to it that the sex instinct stands starkly central and dominating in her life.