During pregnancy, in consequence, the integrity of every structure of the body is tested. A stern, relentless accountant goes over the cells, counts up their reserves, establishes a balance, credits and debits according to the demands of the growing parasite within them. Follow changes in the skin, the bones, the nervous system and the mind. That is, all the glands, subtle recorders, transmitters, producers of the vibrations of change are influenced. But the most influential are the most affected, as the most dominant personalities in a community are most disturbed by a revolution. In Sinclair Lewis' "Main Street," the best novel ever made about America as a nation of villagers, the heroine, Carol Kennicott, has this to say to someone sentimentalizing about maternity. "I do not look lovely, Mrs. Bogar. My complexion is rotten, and my hair is coming out, and I look like a potato bag, and I think my arches are falling,... and the whole business is a confounded nuisance of a biological process." The exploration of the internal secretions has brought us an explanation and an understanding of why child-bearing is a nuisance. We know now that if Carol Kennicott's complexion became rotten and her hair fell out, it was because her thyroid was not adequate to the demands of pregnancy, and that if her arches were falling, and her figure acquiring a potato bag dumpiness, it was because her pituitary was insufficient. In all probability she was a thymus-centered type, which accounts for much of the material that goes to make up the novel. Different endocrine types react characteristically toward the situations of pregnancy. The adrenal type may not be able to respond with the necessary enlargement of its cortex which is normal for the needs of gestation. So pigmentations, darkenings and discolorations of the skin, especially of the face, the traditional chloasma develops. The hyperthyroid type may become sharply exaggerated, almost to the point of mania and psychosis. The subthyroid will suffer an emphasis of her defect, and pass on, because of pregnancy, to the truly diseased state of myxedema, the state of dull, slow, stupid, semi-animal semi-idiocy. The pituitary type becomes more masculinized. The face becomes more triangular and coarser, the chin and cheek-bones more pronounced, and there is a growth of all the bones, so that she is seen to grow visibly in height and breadth, and in the size of the hands and feet. Concomitantly, there is a changed, a more matured and steadier outlook upon life, all due to stimulation of the anterior pituitary, controller of growth, physical and mental.