200 THE GLANDS REGULATING PERSONALITY 



secretion excess or failure. Alternating states of mania and de- 



iflO are caused in some instances by extreme hyperth\ 

 ism. The critical periods of life, when a profound revolution is 

 overturning the endocrine equilibrium, puberty, pregnancy, and 

 the menopause, are the periods of most frequent occurrence of 

 insanity, when mental instability reveals endocrine instability 

 (Dementia precox, pregnancy psychosis, menopause neurosis). 

 Actual insanity need not be the only manifestation. By far the 



■r number of mental disturbances due to aberrations of the 

 internal secretions never see an asylum or a doctor. They live 

 more or less close to the borderline of insanity as persons who 

 have spells, eccentricities and peculiarities, hysteria, tics or just 

 "nervousness." 



About two-thirds of mental deficiency is definitely inherited, 

 about one-third acquired. It is the opinion of a number of psy- 

 chologists that it is inherited as what the Mendelians call a 

 recessive, that is as a trait which will be overshadowed, if there 

 is admixture of normal mentality, but will crop up by breeding 

 with another mental defective. What we know of the endocrine 

 factors in heredity leads us to suppose that it is the mating of 

 one marked endocrine insufficiency with another that is often 

 responsible for the inherited tendency to feeble-mindedness and 

 insanity. The effect of the hormone system upon the vegetative 

 apparatus may create the more obscure insanities and quasi- 

 insanities. The direct action of the internal secretions upon the 

 brain cells, producing a sort of hair trigger situation within 

 them, may cause the explosive discharges from them which 

 pear as overpowering impulses or uncontrollable conduct. The 

 waves of feeling which precede them are unquestionably en- 

 docrine determined. The wave of fear a cat i xj upon 

 seeing a dog is accompanied and indeed preceded by an in* 

 of the amount of adrenalin in the blood. The picture of fright, 

 as observed in a so-called normal person, staring eyes, trembling 

 hands, dry lips and mouth, < adfl to the portrait of the 

 appearance in hyperthyroidism. [np« Dieted with in 



ble impulses, the inhibiting hormones may not be present 

 in sufficient quantity. 



Phehle mlndedness, ranging from stupidity to imbecility, 

 also be a dirt loerine supply I 



sells. \ ooogfa of the thyi 



s blood, brain !>< 



clogged and thickened, so that a gross to the passage of 



