The data obtained in the present investigations were described being separated into four parts.
Part I is devoted to the cytological studies of normal, abnormal mature ova and polyovular follicles in mature mice, Mus musculus (Swiss albinos) during the normal sexual cycle. It was found that the atretic follicles of large size in which the ova were in a course of maturation were very abundant in number in ovaries of mature mice. It seems probable that the course of degeneration takes place in both egg body and granulosa cells, and that the results affect the hormone secretion in the mature ovary. The polyovular follicles were found to be rather rare in occurrence both mature and immature mice.
In Part II is described an cytological effect of sex stimulating hormones on large abnormal follicles and ova in Mus musculus (Swiss albinos). The experiments were carried out by two ways. The first dealt with the effect of the mixture of anterior pituitary sex gland stimulating hormone and sex gland stimulating hormones from placenta upon the fate of abnormal follicles. The second was to examine the effect of the mixed hormones as above and the pregnant mare serum of horse upon abnormal follicles.
On the basis of the results of the present observations, the conclusion is possible that the reduction in number of abnormal mature ova may be explicable by the effect of sex stimulating hormones. Also, the evidence presented in the two experiments has indicated that abnormal mature ova showed a remarkable decrease in number in pregnant mare serum treated mice. Especially, the hormone administration probably affects only the follicles of larger size. Further, the number of abnormal ova showing an immature condition of granulosa cells is remarkable. From the results of the present study, it is presumed that abnormal mature ova which failed to ovulate may undergo ovulation under the effect of the sex stimulating hormones.
Part III describes the results of the cytological investigation of some comparative features of normal, abnormal mature ova and polyovular follicles in mature ovaries of the following mouse strains: Swiss albinos, D-240 albinos, B-72 albinos and dd/Ma albinos. There is no remarkable difference in number of normal, abnormal mature ova and polyovular follicles by mouse strain.
Part IV gives accounts of the histochemical observations of normal and abnormal ova in mature ovaries of mice studied at four stages of the oestrous cycle. The occurrence and localization of glycogen and RNA were the subjects mainly dealts with in ovaries of Mus musculs (Swiss albinos and D-240 albinos). The data derived from this experiment indiacted that the primary and secondary normal ova in mature ovaries contained a varying amount of glycogen, that in a few individuals the ova contained no glycogen, and further that the atretic ova of large size contained always glycogen. Normal ova observed in both primary and secondary follicles showed a weak reaction to the test for RNA. This seems to suggest that the follicles contain a small amount of RNA. A few atretic ova preceding beyond the maturation course showed a reaction indicating the presence of a small amount of RNA.