This stage corresponds with that in which the young of oviparous animals breaks the shell and escapes. The human being however, undergoes a remarkable change, and remains in the womb for a period longer than that already past, in order to become more perfected. From four to nine months the development is proportionally much more rapid than during the first four months, owing to the circulation of perfect red blood, which is now found the same as in the adult, and is probably derived from the mother's blood vessels. _Five months._ Every part is considerably increased in size, and become more perfect. The lungs enlarge, and are even capable of being, to a certain extent, dilated. The skin becomes much stronger. The situation of the nails can be discerned. The meconium is more abundant, and lower down in the intestines. The length is now eight or ten inches, and the weight fifteen or sixteen ounces. _Six months._ The nails are marked. The head becomes downy, from the first development of the hair. A little fat is formed. Length twelve inches, weight from one and a half to two pounds. No indications of intellectual faculties. _Seven months._ The whole being has rapidly progressed. The nails are formed, the hair is perfect, in the male the testicles descend to the scrotum, and in the female the ovaries reach the brim of the pelvis. The bones are tolerably firm, and the meconium collects in the large intestines. Length fourteen inches, weight about three pounds. Intellectual functions not yet exercised. The two remaining months are merely devoted to further increase in size and weight. No new phenomena present themselves. _Nine months._ Every function has become active. The skin becomes colored, and perspiration occurs. There are no indications of the intellectual functions, but the animal functions are remarkably active, particularly that of _taste_, which no doubt leads to the act of sucking, from the natural desire for its gratification. The child can now experience all the ordinary sensations of pain, hunger, heat, and cold, and is capable of preserving an independent existence if brought into the world. Plate XII. represents a section of the Uterus at about one month of gestation, so as to show all the parts in their proper situation. PLATE XII.