EXPERIMENTAL PRODUCTION OF HYPOTYPICAL OVARIES. 95 



granulosa degeneration sets in, leading to a complete solution of 

 the granulosa cells with subsequent ingrowth of connective tissue 

 resulting in various stages of connective tissue atresia. Follicles 

 in the last stages of connective tissue atresia form a prominent 

 part of the ovaries. Neither a new corpus luteum nor a remnant 

 of a retrogressing corpus luteum visible. The last ovulation 

 had therefore taken place more than four weeks previous to 

 examination. The uterus is thin, with relatively low epithelium 

 and small glands. Much secretion is present in surface epi- 

 thelium and some gland ducts. The mucosa is thin and fibrillar. 



In the four guinea pigs in which ten days or more had elapsed 

 since the beginning of the experiment the ovaries had become 

 hypotypical; while in guinea pig B, which was examined six 

 days after the beginning of the experiment, degenerative changes 

 took place in the large follicles, probably preparatory to the 

 ensuing hypotypical changes. In this animal the relative loss 

 in weight had been almost as marked in six days as in the other 

 guinea pigs in a longer period. It seems therefore that a mini- 

 mum time has to elapse before the hypotypical condition of the 

 ovaries is established. The latter can be obtained in one of 

 the following two ways: First, after the degeneration of all the 

 good-sized follicles following ovulation, the small follicles fail 

 to reach full size. Before they have grown to medium size, the 

 granulosa cells perish and connective tissue grows in. Second, 

 the large follicles degenerate perhaps at a somewhat accelerated 

 rate without an ovulation having preceded this change, and 

 the small follicles fail to reach medium size. The granulosa of 

 the small-medium follicles does not show the karyorrhexis 

 affecting simultaneously a large number of the granulosa cells 

 and characteristic of the beginning atresia of large follicles; 

 isolated granulosa cells may, however, show karyorrhexis. 



In all of the animals with exception of guinea pig D ovulation 

 had probably taken place within the last month; and in two 

 animals within the last two weeks preceding the time of examina- 

 tion. We are therefore justified in assuming that at the begin- 

 ning of the experiment the ovaries had been fully developed in 

 these -animals in accordance with their initial weight and age. 

 The lack of a sufficient amount of food however prevented 



