I 



442 REPRODUCTION AND DEVELOPMENT 



of the sperm and ovum after coitus would seem to indicate that were 

 all the concerned organs normal, fertilization would almost invariably 

 follow a normal copulation, as is the case in general with the brutes that 

 are the less artificialized by domestication. 



The means by which the fertilized ovum is transported down the tube 

 to the uterine cavity have been already described. The cilia lining the 

 different divisions of the tube bear it along at a slow rate, while develop- 

 ment goes on. Several days, probably about six (2 cm. daily), are re- 

 quired for the ovum to reach the uterus, which meanwhile has been 

 making ready for it. The mucosa of the uterine fundus has hypertrophied 

 and become soft and active from increased vascularity, and the blood- 

 vessels extend outward to form long villi. This new-growth is known as 

 the decidua vera, and it forms a soft nest for the segmenting ovum when 

 it arrives from up the tube. Meanwhile the outer covering of the ovum 

 has been changing somewhat similarly, so that when it reaches the uterus 

 its villi soon interlock with those of the uterus. It thus becomes in a 

 short time firmly embedded. Then the decidua vera grows upward about 

 the ovum (forming the decidua reflexa), and shortly encloses it. The 

 growing ovum is embedded firmly in this way in a soft and vascular 

 matrix, with which for nearly ten lunar months it can develop, growing 

 meanwhile after an inherent pattern of its own yet influenced more or less 

 by many conditions in its maternal environment. 



PREGNANCY, PARTURITION, AND LACTATION. 



Inasmuch as the direct influence of the father ceases with the fertiliza- 

 tion of the ovum, we may now turn our attention wholly to the means 

 by which the child is fostered in its mother's womb, born " into the world," 

 and nourished until fitted to eat food other than mother's milk. These 

 three processes are respectively pregnancy, parturition, and lactation, 

 and because the subject-matter of an art and science by itself (obstetrics), 

 they require here but relatively brief discussion. 



Pregnancy is that physiological period, in round numbers forty weeks 

 long, which elapses between the fertilization of the ovum and the begin- 

 ning of the child's expulsion from its mother's belly. Too often, perhaps, 

 it is looked upon as other than a normal functional part of a woman's 

 life, but biologically woman is female only for this purpose. 



The physiological changes which occur in the maternal psychophysical 

 organism during pregnancy affect in some degree nearly all its aspects. 

 We may divide them into three classes : those which concern respectively 

 the reproductive system proper, the remainder of the body, and the 

 mind (Edgar). 



THE CHANGES IN THE REPRODUCTIVE ORGANS in pregnancy are such 

 as one would expect to find in any organic apparatus during a period 

 of functional activity, namely, an all-round development. The body's 

 changes in general are all directed to this end of supporting the addi- 

 tional activity of the sexual system. 



