REPRODUCTION 143 



In perfectly healthy women the other body func- 

 tions are scarcely affected by the recurrence of the 

 menstrual period. There is usually some slight lack of 

 well being and the woman's efficiency is not quite up 

 to the normal standard. Any further symptoms must 

 be referred not to menstruation but to some diseased 

 condition affecting either the generative or some ad- 

 jacent viscera. 



The ovum (egg) is probably carried into the fallopian 

 tube by the cilia on its extremity, and meets the male 

 cell (spermatazoon) shortly after the entrance of the 

 ovum into that tube. Usually the now fertilized ovum 

 is swept into the uterine cavity and becomes attached 

 to the wall of the uterus where the placenta is formed 

 and remains until the termination of pregnancy; but, 

 owing to unknown causes, the impregnated ovum is 

 sometimes arrested in the tube and an effort is made to 

 produce the fetus in that narrow passage. This is a- tubal 

 pregnancy, whose natural history ends in rupture of 

 the tube and the death of the mother, unless the con- 

 dition is discovered and relieved by surgical interfer- 

 ence. In rare cases the ovum is impregnated in the 

 peritoneal cavity, never entering the tube, constituting 

 a true abdominal pregnancy. 



The placenta is the organ which conveys air and nour- 

 ishment to the fetus during uterine life. The fetus is 

 never in contact with the mother's blood, and, though 

 its OAvn heart beats, is dependent upon the maternal 

 heart to drive blood containing both food and oxygen 

 into the placenta from which it is carried into the fetal 

 vessels. Between the fetus and the mother's blood are 

 interposed tissues which permit diffusion through them 

 in a way similar to that by which the mother's own 

 tissues are nourished by her blood stream, In other 



