12 ON GERMINAL TRANSPLANTATION IN VERTEBRATES. 



left incision. Ten and a half months later the animal was killed. The 

 uterus was well nourished. There was no tissue at the sites of the original 

 ovaries, but attached to the border of the greater omentum was a typical 

 ovarian mass which showed microscopically plenty of ovarian tissue and 

 at least one large ovarian follicle. This case is interesting as showing that 

 presence of ovarian tissue in immediate contact with the genital ducts 

 is not necessary to prevent atrophy of those ducts. An ovary attached to 

 the digestive tract (or doubtless anywhere else in the body) serves equally 

 well to prevent genital atrophy. Some substance liberated by the ovary 

 and circulating in the blood is doubtless the active agent in maintaining 

 the full development of the uterus and the recurrence of rut. 



In guinea-pig No. 73, one year old, the grafts were placed, one attached 

 to the right body-wall, the other merely dropped into the abdominal cavity. 

 Nine and a half months later the animal was killed. There was little or 

 no genital atrophy, and at the site of the graft on the body- wall a small 

 mass was found which was identified by microscopic examination as the 

 oviduct of the graft, with a small amount of degenerating ovarian tissue, 

 without follicles. There was no sign of regenerated tissue at the ovarian 

 sites. 



The above six cases show that normal ovarian tissue persisted in its new 

 environment for periods from four months to ten and a half months. They 

 demonstrate that the position of a homoplastic graft may be varied to any 

 place on the peritoneal surface; and that the grafted ovary may attach and 

 nourish itself without the aid of sutures. 



The failure of these foreign ovaries to bring about pregnancy inclines 

 one to the idea that the ovum when mature and liberated may be more 

 subject to resorption during its migration to the uterus than the more prim- 

 itive tissue from which it was discharged. It is also well to remember that 

 Graafian follicles have been found to be less in number and larger in size 

 in grafted tissue than in normal tissue (Carmichael, Sauve). Further, 

 in the case of an ovary removed from its normal position, the chances are 

 necessarily greatly diminished that the egg when liberated will find its way 

 into the oviduct. In an ovarian operation there is also great danger that 

 the open end of the oviduct will become permanently closed in consequence 

 of injury. On the whole it is not surprising that foreign ovaries often 

 persist without bringing about pregnancy. 



Group III. 



This group includes ten cases in which, in spite of a supposed perfect 

 castration, the animal regenerated ovarian tissue at the original site. Three 

 of these animals bore young. In all ten cases regenerated ovaries were 

 found post mortem by inspection and microscopic examination. The color- 

 character of the young indicated that they had probably come from regen- 

 erated tissue, and the autopsy in all cases confirmed this view. 



