186 THE REPRODUCTIVE SYSTEM. 



tion of the connective tissue, forming a sort of scar or cicatrix, 

 the corpus luteum is finally obliterated. 



The whole process is similar to that by which wounds in 

 general undergo repair. 



The corpora lutea which result when the discharged ovules 

 are fecundated (the so-called "true" corpora lutea) attain a 

 larger size and continue in existence a much longer time (for 

 many months) than do those (the " false " corpora lutea) 

 when pregnancy does not result. 



Obgenesis : The ovary is similar in development to the testicle and 

 complementary to it in function. Both are organs of high vital 

 importance, being the essential genital glands and seats of repro- 

 duction. 



The observations made above with respect to spermatogenesis 

 apply also, mutatis mutandis, to oogenesis, the development of ovules. 



The ovary, like the testicle, has an ample blood-supply and a less 

 conspicuous innervation. These two channels, circulatory and nervous, 

 are the only apparent means of communication by which conditions 

 in other parts of the maternal body can influence the ovary and 

 hence be transmitted to the offspring. That the ovary can in such 

 way act in sympathy with organs not directly connected with it 

 is shown by the relations between ovulation, menstruation, and 

 pregnancy. 



As to the transmission of racial and hereditary characteristics from 

 the ovum of one generation to the ovules of the next through a suc- 

 cession or continuity of special germ-cells, the same considerations 

 apply in oogenesis as in spermatogenesis. Some differences in action 

 of the female and male genital glands may be noticed. All the ovules 

 discharged by the human female exist in the ovary preformed from 

 birth ; consequently any acquired characters in the mother, if trans- 

 mitted to offspring, would have to be impressed upon cells already 

 formed rather than upon cells to be subsequently developed. The 

 spermatozoa and spermatogenic cells, on the contrary, are being 

 continually renewed and developed de novo. Of all the primitive 

 ovules in the ovaries only a few hundred come to maturity in the life- 

 time of the human female ; in contrast to this the male produces and 

 disseminates millions of spermatozoa. 



The oviducts, or Fallopian tubes, are conical tubes opening 

 into the uterus by the small end and into the peritoneal cavity 

 by the large end, which is fimbriated. The wall of the ovi- 

 duct consists, from within outward, of mucous, submucous, 

 muscular, and serous coats. The mucous coat is formed by a 

 single layer of columnar ciliated epithelium-cells resting on a 

 firm tunica propria. At the margins of the fimbria3 the 



