374 B. F. KINGSBURY 



Accompanying the centrifugal wave of differentiation and 

 growth there is a progressive advance in the state of development 

 attained. Early in development (antepartum) large genitoid 

 cells appear in the central portion mainly in the medullary cords. 

 These disappear. The earliest follicles are central but do not 

 attain large size of advanced development but degenerate. After 

 birth (thii'd week), come the irregular medullary follicles which, 

 however, degenerate. An irregular centrifugal wave of degen- 

 eration might therefore be said to follow after the wave of 

 differentiation. 



The wave of differentiation and growth does not run through 

 to completion but in the periphery proceeds much more slowly, 

 leading, therefore, to the establishment of a cortex in which the 

 follicles remain long in a resting stage, as the well-known primary 

 follicles. 



Degenerations affecting follicles of all stages of development 

 occur at all periods of the life history as well. The small and 

 immature ovary of the anti- and postpartum periods is obviously 

 'unable' to provide adequate blood supply for the follicles be- 

 ginning development during these periods and hence the sugges- 

 tion at once arises that therein is to be found the reason for the 

 profound degenerations occurring in the pre-sexual period and 

 after sexual maturity; that the processes, which in the adult ovary 

 lead to the formation of the mature Graafian follicle, are opera- 

 tive from the beginning but continually fail, due to the absence 

 of the necessary conditions (nutritive or otherwise) reaching pro- 

 gressively more advanced stages as development and growth pro- 

 ceed. The lack of proper vascular and nutritive conditions is 

 doubtless the cause of many of the degenerations^ (atresia folliculi; 

 degenerations of primary follicles) particularly in the adult period. 

 Inasmuch as it is extremely doubtful if the developmental 

 factors are all intrinsic — that is, the growth and differentia- 

 tion within the ovary independent of the rest of the organism- 

 it is equally improbable that all the degenerations of the growth 



* Compare the conclusions of Clark, from the study of injected human ovaries, 

 inmiature and adult. J. G. Clark. Johns Hopkins Hospital Reports, vol. 9, 1901 : 

 pp. 593-676. 



