. Journal of anatomy . what are the causes of descent of the humantesticle, and the approximate explanation is as follows:— The disappearance in great part of the Wolffian body, and the guidanceas a rudder, but not as a tractor, of the inguinal fold (gubernaculum at thisstage), determine the position of the testes near the internal abdominal ringat or about the 3rd month (fig. 26). The subsequent hypertrophy of the dev^eloping gubernaculum and itsappearance in the peritoneal cavity as a thickened projection analogous tothe conus inguinalis, if we follow Klaatschs specimens of this period, caus
. Journal of anatomy . what are the causes of descent of the humantesticle, and the approximate explanation is as follows:— The disappearance in great part of the Wolffian body, and the guidanceas a rudder, but not as a tractor, of the inguinal fold (gubernaculum at thisstage), determine the position of the testes near the internal abdominal ringat or about the 3rd month (fig. 26). The subsequent hypertrophy of the dev^eloping gubernaculum and itsappearance in the peritoneal cavity as a thickened projection analogous tothe conus inguinalis, if we follow Klaatschs specimens of this period, causea temporary ascent of the testicle. The hypertrophy with increased pro- 12 Dr D. Berry Hart jection into the peritoneal cavity is a fact, whatever view as to its analogyto the conns in rodents we adopt, and has the result of causing the testisto lie higher. It may also have a dilating eifect on the processus vaginalis;but as I have already said, there is more probably a combined growtli ofgubernaculum and Fl<;. 26.— A traiisparent prepaiutiuii of tlie riglit testis of anembryo pig, 210 mm. in length x 6. Left testis nearly in inguinal canal ; right testis, T, justentered ;K, right liiihiey; A, dorsal aorta; E, epididynius; U,ureter; K, rectum; , , Miillerian and Wolffianducts; , umliilical artery. (Eben. C. Hill.) The next stage (6th month to 8th month) is probably an increase in thecapacity and length of the processus vaginalis, so that it expands and growsup, as it were, over the testis, enclosing it in the inguinal canal (fig. 28). Owen has suggestive remarks on the presence of the more or less completeovarian peritoneal capsule of tlie ovaries found in many mammals. In the whitebear {Ursus ) llie ovaries are completely enclosed in a reflected capsule ofthe peritoneal membrane, like the testes in the tunica caginalis : a small opening,however, leads into the ovarian capsule at the part next the horn of the uterus {, § 99).
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectanatomy, bookyear1867
