31 6 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



layer of smooth muscle fibers. Externally the tube, 

 is practically enclosed by the peritoneum, forming a 

 serous covering. 



Embryologically, each Fallopian tube represents a 

 Mlillerian duct, which is derived from the mesoderm. 

 In the male the Wolffian duct develops into the vas 

 deferens. This duct, which is rudimentary in the 

 female, is called Gartner's duct, and lies parallel to 

 the Fallopian tube, between the latter and the round 

 ligament. The round ligament extends from the 

 uterus to the internal abdominal ring in nearly the 

 same position as the vas deferens does in man. 



Fertilization, as a rule, takes place in the upper 

 part of the Fallopian tube. In cases of tubal preg- 

 nancy the ovum does not reach the uterus but finds 

 lodgment in the tube. The much-folded mucous 

 membrane allows considerable distention, but ulti- 

 mately the rapidly growing embryo ruptures the 

 tube, with serious complications resulting from in- 

 ternal hemorrhage. Usually the ova pass down the 

 tube on the corresponding side, but it is possible for 

 the ova from one ovary to pass down the tube of the 

 opposite side. Experimentally, the right ovary and 

 the left tube may be removed in the dog and the ani- 

 mal still become pregnant. 



The ovaries have a marked influence on the devel- 

 opment and mentality of a woman and their removal, 

 prior to the menopause, is followed by deleterious 

 results, much the same as the removal of the testes 

 in the male. While extracts from certain organs, 

 such as the thyroid gland and the suprarenal bodies, 

 have specific medicinal properties, extracts from the 



