This incloses the fluid--the _liquor amnii_--which serves to protect the fetus from blows or sudden jars. The membranes and the contained fluid form what is known as the “bag of waters.” Not rupturing before birth, they make what is called a _veil_ or _caul_ over the child’s face, to which is attached various superstitions, such as the gift of “second sight,” clairvoyance, etc. HEALTHY NUTRITION of the _fetus_ depends entirely upon the mother. The placenta not only represents the digestive organs, but the lungs of the _fetus_. Consequently upon the condition of the mother depends the condition of the child. It has no other means of getting nutriment, or of disposing of waste material. After birth it has the same advantage as the adult in correcting errors in diet and nutrition by elimination. The skin, with its miles of perspiratory ducts, then conveys effete matter from the system, the lungs keep up by respiration a constant interchange of oxygen for carbon, while the liver, kidneys and bowels are active in their functions of depurition. _In utero_ these functions are all dormant, consequently giving the fetus a disadvantage for healthy growth. Mothers often show a great solicitude about diet and conditions during lactation, while they are comparatively indifferent to these matters during pregnancy. Especially should they breathe deeply, and that, too, of pure air. Trall says: “If the mother does not breathe sufficiently the child must suffer. Many a mother gives birth to a frail, scrofulous child, for no reason except that during the period of gestation she is too sedentary and plethoric. I have known women of vigorous constitutions, who had given birth to several healthy children, become the mothers of children so puny and scrofulous that it was impossible for them to be raised to adult age. The reason is that the mother is obstructed in her respiratory system, and although she may breathe enough to sustain her own organization in a fair condition, she does not inhale oxygen enough to supply the needs of an intra-uterine being. Many ‘still births’ are explainable on this principle.” THE DURATION OF PREGNANCY is nine calendar months or ten lunar months, about 280 days. If the date of impregnation is not known, the _count_ should be made from the beginning of the last menstruation, and add eight days on account of the possibility of its occurring within that period. It is possible in some diseased conditions for the period to extend much beyond this time. I knew one case of amniotic dropsy where pregnancy extended forty-four weeks.