72 THE GLANDS REGULATING PERSONALITY 



phosphorus-containing substances of the general nature of those 

 found in the central nervous system than any other gland or non- 

 nervous tissues in the body. During human intrauterine life the 

 adrenal glands are large and conspicuous, in the first half of the 

 second month being twice as large as the kidneys. Most of this 

 relatively huge size, which happens in the human alone, and not 

 in other animals, is due to enlargement of the cortex. Should this 

 preponderance of the cortex over the medullary portion not occur 

 in the human, that is, if the proportions remain like those of 

 other animals, the brain fails to develop properly, or an entirely 

 brainless monster is generated. The human brain, therefore, 

 probably owes its superiority over the animal brain, to the adre- 

 ~ nal cortex, in development anyhow. The growth of the brain 

 cells, their number and complexity is thus controlled by the 

 adrenal cortex. 



• Besides its action upon the sex cells and the brain cells, the 

 :•— internal secretion of the adrenal cortex acts upon the pigment 

 -^ cells of the skin, blunting their sensitiveness to light. In degene- 

 ration of the interior of the gland, which destroys the medulla, 

 but not the cortex, the color of the skin is left unmodified. If, 

 however, the cortex is invaded, as happens most often in the 

 classical tuberculosis of the adrenals which drew the attention of 

 the Englishman Addison to them, then a darkening of the skin, 

 which may go on to a negroid bronzing, follows. That means an 

 increased sensitiveness of the pigment cells of the skin to light. 

 Skin color control may therefore be looked upon as an adrenal 

 cortex function. 



So much is known about the adrenal cortex. Upon the medulla, 

 the interior gland of the gland, there has been lavished an 

 amount of attention beside which the cortex is to be classed as a 

 neglected wall-fiower. Nearly everything that possibly could be 

 determined about an internal secretion has in its case been settled 

 or plausibly guessed at. The cells manufacturing the secretion, 

 its exact chemistry and function, its action upon the blood, the 

 liver and spleen, the heart and lungs, the brain and nervous sys- 

 tem, have been minutely investigated, studied and charted. Its 

 source in the food, its fate in the body, its place in the history 

 of the individual and the species, its importance as a weapon 

 in the struggle for existence, and the survival of the fittest have 

 meo made the subject of an astonishing number of researches, 

 considering the short period of scarce three decades that inten- 

 eive sci. centered its barrage upon it. 



