are the reverse of cretinism and myxedema.  There is an over-excitability of the nerves in place of sluggishness, and an over-reactivity of the whole organism to its environment.  The heart’s action is too fast, and under the slightest stimulus gets faster to the point of obtruding itself into the conscious mind as a palpitation.  Instead of the lowered temperature and coldness of the cretin, there is a heightened temperature, one or two degrees above the normal, and a feeling of heat.  The individual has a high warm color, does not sleep well, becomes or remains thin no matter how much he or she eats, is abnormally susceptible sexually, may suffer from a definite insomnia, is emotional, and perspires freely.  Alert, neurotic or high-strung, magnetic, and imaginative are some of the descriptive adjectives applicable.  The eyes are bright and prominent, large and beautiful, when they have not reached the stage entitled “pop-eyed.”  Or they may even become so protuberant and bulging as to develop the expression of one staring aghast at some ineffable horror.  The latter is the feature of only the severest types, when there is an associated goitre, the combination designated as exopthalmic goitre.

There are, too, individuals in whom hyperthyroidism and hypothyroidism are mixed, or rather alternate.  At one time they present the phenomena of the one, at another of the other.  They are the people who complain of the cyclic quality of their moods and purposes.  Their mood will be a heaven of exaltation and exhilaration, and then descend into a slough of despond from which they feel themselves inextricable.  They are always talking about the ups and downs of their mental states.  Headache and languor and fatigability, dry skin and lack of appetite for food or exertion on one day or for one week, give way on the next day, or for the next week, to an energetic gayety, and sweaty, flushed skin, a prominent appetite for food and every sort of activity.  Driven to be forever on the go, for one period, in the next they feel like lying down most of the day, with no inclination for any life whatever.  The stage of depression may go as far as a melancholia, the stage of stimulation as far as mania.  They may simulate manic-depressive or cyclic insanity.  Something restrains them, and holds them bound as in a vise in the one cycle.  And then they are driven on beyond themselves by some invisible whip in the next.

THYROID AS DIFFERENTIATOR

Besides the action of the thyroid as energizer, lubricator, and growth catalyzer, it has a remarkable power as a differentiator of tissues.  It determines the embryonic etchings of the different organs which in their totality comprise the unique individual.  Every multicellular animal must first have existed as a single cell, the impregnated ovum.  With the body and personality of the ovum, the creature is one and continuous, literally something the single