Mammalian Ova within a Uterine Foster-mother. 179 



meriting ova. But that was not all : I had a stock of fourteen 

 Belgian Hare does, and of the four which were operated on to receive 

 the ova from the four Angora does, three of them died under chloro- 

 form and only one bore young, and she had only one young one, and 

 that one was a Belgian Hare. 



In 1896 I again attempted the same experiment, using this time 

 Dutch and Belgian Hare rabbits ; and again I failed, but from a 

 different cause. The Dutch rabbits produced segmenting ova, and 

 the Belgian Hare does stood the operation perfectly satisfactorily, 

 but they were bad breeders. Two of them had only one young one 

 each, one had two, and one six young ones ; they were all undoubt- 

 edly Belgian Hares. 



These Belgian Hare does I had kept for one, some of them for two 

 years, without allowing them to breed, and I am inclined to think that 

 was the reason why they were not so prolific as usual. I considered 

 also that their disinclination to breed might operate adversely on the 

 foreign ova which were introduced, and so check their development. 



This year I made hve experiments, using again Dutch and Belgian 

 Hare rabbits. The method adopted was the same as that already 

 described. A Dutch doe was covered by a Dutch buck, twenty -four 

 or thirty hours later a Belgian Hare doe was covered by a Belgian 

 Hare buck; the Dutch doe was then killed, and segmenting ova, by 

 this time divided into two or four segments, were taken trom her 

 fallopian tube and placed into the open anterior end of the fallopian 

 tube of the Belgian Hare doe. 



The operation is a very simple one. The Belgian Hare doe is put 

 under anaesthetics and stretched out on her stomach. A longi- 

 tudinal incision, 2 in. long, is then made through the skin at a place 

 1-J to in. from the anterior edge of the pelvis, and on a level with 

 the ventral bordei of the lumbar muscles. A smaller incision is then 

 made through the body- wall just ventral to the lumbar muscles, and 

 the anterior end of the fallopian tube is readily found and pulled out 

 through the opening with the help of a pair of forceps. The foreign 

 ova are then taken out of their maternal fallopian tube on the point 

 of a spear-headed needle, the foster-mother's infundibulum is held 

 open with a pair of forceps and the ova placed well within the 

 anterior end of her fallopian tube ; after pushing the latter gently 

 back again and washing with some antiseptic solution, the wound is 

 sewn up and dressed with collodion and cotton-wool. 



In one case the rabbit died under anaesthetics before the opera- 

 tion began, from heart failure (degeneration), but in the other four 

 cases the recovery was rapid and no discomfort even shown, after 

 the effects of the anaesthetic had worn off. 



Of these four experiments, in one case the Belgian Hare doe 

 proved barren; in another she gave birth to eight Belgian Hare 



