EXPERIMENTAL PRODUCTION OF HYPOTYPICAL OVARIES. IO5 



fibrous tissue. In this case the ovaries are not yet hypotypical, 

 but the lack of good medium and large follicles indicates that 

 some inhibition in the growth of follicles occurred, while the 

 large follicles that had developed previously failed to mature and 

 degenerated. 



Guinea Pig No. V. Weight June 30, 439 grams; July 9, 289 

 grams. From July 10 on a full ratio of food was given daily 

 and the animal gained in weight. On July 21 it weighed 396 

 grams; it had not yet regained its original weight. On that 

 date it was examined. Ovaries: Contained an atretic yellow 

 body (remnant of a corpus luteum). Good follicles of all sizes, 

 including good large follicles. Large follicles in granulosa de- 

 generation and in various stages of connective tissue atresia. 

 Mammary gland: Small intermediate, no mitoses. In this case 

 the ovaries are on the whole normal; but apparently mature 

 follicles did not develop and an ovulation had not taken place 

 for a long period of time previous to the examination, despite 

 the fact that the animal had regained part of its weight. 



We find then in this series that hypotypical ovaries did not 

 develop as the result of underfeeding; but in Guinea Pig Nos. 

 II., III., and IV. we find some changes which indicate a tendency 

 toward the development of hypotypical ovaries; either a pre- 

 mature atresia sets in in follicles which are only of medium size, 

 or even smaller, or at least a retardation in the development 

 of large follicles apparently occurred toward the end of the experi- 

 ment. In all cases mature follicles were absent and ovulation 

 was delayed. In the one animal which received a full ratio of 

 food after a preceding period of underfeeding the follicles like- 

 wise failed to mature and ovulation failed to take place during 

 the period in which the animal gained in weight. It is, however, 

 possible that the delay in ovulation was not exclusively due to 

 the undernourishment. In one case abortion had in all prob- 

 ability taken place previous to the examination, probably as 

 the result of the underfeeding. In all these cases the relative and 

 especially the absolute loss of weight had been as great as in the 

 guinea pigs of the III. and IV. series, or it was even greater, and 

 yet hypotypical ovaries had not developed. This result may 

 be due to the greater weight of the animals at the beginning of 



