The same factors that produce the accidents of embryology resulting in malformations or monstrosities in the human family, are also operative in the case of our lesser brethren of the animal kingdom, for monstrosities and birth-defects are very common among the lower animals, notwithstanding the fact that the animal mother probably does not "believe in birthmarks." "It is a striking fact that during the nineteenth century, the teratologists, those who have scientifically investigated the causes of monstrosities and fetal morbid states, have almost without exception, rejected the theory of maternal impressions." Scientists and physicians are coming to recognize the fact that fears and frights do not in any way act as causes in the production of monstrosities and deformities. Let us seek forever to liberate all womankind from the common and harassing fear and the definite dread and worry that, because they failed to control themselves at the instant of some terrifying sight or experience, they were directly responsible for the misfortune of their abnormal offspring. It should be remembered that there exists no direct connection whatsoever between the nervous system of the unborn child and the nervous system of the mother. The only physiological or embryological relationship is of a nutritional order, and even that is indirect and remote. ROLE OF THE PLACENTA By the end of the third month, the "cocoon" attachment described in chapter two has disappeared; the fetus is slowly pushed away from the uterus which has so snugly held it for more than eleven weeks; while upon the exact site of its previous attachment the thickened uterine membrane undergoes a very interesting and important change--definite blood vessels begin to form--which begin indirectly to form contact with the maternal vessels, and thus it is that the placenta, or "after birth" is formed; and then, by means of the umbilical cord, nourishment from the mother's blood-stream is carried to the growing and rapidly developing child. In exchange for the nourishing stream of life-giving fluid by which growth and development take place, the embryo gives off its poisonous excretions which are carried back to the placenta, from which they are absorbed into the veinous circulation of the mother; so, while the mother does, through the process of nutrition, influence growth and development in the embryo, she is wholly unable to produce specific changes and such definite developmental errors as birthmarks and other deformities.