CHAPTER I. 



MENSTRUATION. 



FROM puberty, which occurs at from 13 to 17 years of age, to the 

 climacteric, which arrives at from 45 to 50 years of age, the human 

 female is subject to a monthly discharge of ova from the ovaries, 

 accompanied by special changes, not only in those organs but also 

 in the Fallopian tubes and uterus, as well as by general changes in 

 the body at large, the whole constituting 'menstruation.' The 

 essential event in menstruation is the escape of an ovum from its 

 Graaffian follicle. The whole ovary at this time becomes con- 

 gested, and the ripe follicle bulges from its surface. The most 

 projecting portion of the wall of the follicle, which has previously 

 become excessively thin, is now ruptured, and the ovum, which 

 having left its earlier position, is lying close under the projecting 

 surface of the follicle, escapes, together with the cells of the discus 

 proligerus, into the Fallopian tube. How the entrance of the 

 ovum into the Fallopian tube is secured is not exactly known. 

 Some maintain that the ovary is grasped by the trumpet- shaped 

 fimbriated mouth of the Fallopian tube, itself turgid and con- 

 gested ; the movements necessary to bring this about being effected 

 by the plain muscular fibres present in the mouth of the tube. 

 Others, rejecting this view, and asserting that the turgescence 

 of the tube does not occur until after the ovum has become 

 safely lodged in the tube, suggests that the ovum is carried in the 

 proper direction by currents in the peritoneal cavity set up by the 

 action of the ciliated epithelium lining the tube, currents whose 

 direction and strength seem, as shewn by experiment, to be 

 adequate to carry into the uterus particles present in the perito- 

 neal fluid. Arrived in the tube, the ovum travels downwards, very 



