But all the sufferings of pregnancy and childbirth are compensated for by the ardent desire of the normal woman to have a child, and by the happiness of hearing its first cry. Proud and happy to give life to a new human being, which she hopes soon to suckle and carry in her arms, she cheerfully bears all the inconveniences and pains of pregnancy and childbirth. The latter is actually painful, for in spite of all that nature does to relax the pelvis and render it elastic, to dilate the neck of the womb, the vagina and the vulva, the passage of the enormous head of a human infant through all these relatively narrow apertures is extremely difficult (Figs. 22 and 23). The passage is forced by the powerful contractions of the muscles of the womb. However, they do not always succeed by themselves, and in this case the accoucheur is obliged to apply the forceps to extract the head of the child. Very often the neck of the womb, the vagina or the perineum (the part situated between the anus and the vulva) become torn during labor, and this may lead later on to disorders such as prolapse of the womb, etc.; disorders which may last through life. When the child is born, the umbilical cord (that is the transformed allantois, Fig. 23) cut, and the placenta extracted, the connecting nutrition and respiration between the child and its mother are suddenly interrupted. Nourished hitherto by its mother's blood through the placenta and the vessels of the umbilical cord which supplied the necessary oxygen, the infant is suddenly obliged to breathe and feed for itself. Its lungs, hitherto inactive, expand instantaneously under the nervous influence produced by the blood saturated with carbonic acid, and the first cry is produced. Thus commences individual respiration. Several hours later the cessation of maternal nutrition causes hunger, and this the reflex movements of suction, and the child takes the breast. During this time the empty womb contracts strongly and retracts enormously in a few days. The increase of blood produced by the maternal organism, by its adaptation to the nutrition of the embryo, is then employed in the production of milk in the breasts or lactiferous glands, which were already well developed during pregnancy. =Suckling. Maternity.=--The mother is instinctively disposed to suckle her child as the infant is to suck. At the end of four to six weeks, the womb has almost completely regained its former size.