INTERSTITIAL CELLS OF MAMMALIAN OVARY 83 



characteristics in their formation Benthin ('H); Schaeffer ('11). 

 There ha\'e l^een a number of investigators whose work has shown 

 clearly that in man atresia folliculi, and interstitial cell formation 

 follows the same plan as in the cat, for example. Grohe ('63) 

 showed that before puberty Graafian follicles were continuously 

 formed. Slavjansky ('74) described atresia in ovaries from 

 childhood, the sexually mature and during pregnancy. Schott- 

 lander ('91, '93), and Hoelzl ('93)— the latter in a series of 60 

 cases from 1 year to 71 years of age — added several histological 

 details, calling attention to the prominence the large cells of the 

 theca (i.e., interstitial cells) may attain. H. Rabl ('98) made a 

 careful study of atresia (25 cases) and supplemented it by com- 

 parative observations. He recognized the interstitial cells as 

 "nothing more than hypertrophied stroma cells." Clarke, Bos- 

 hagen, Pinto, Friinkel, Seitz, Fellner, Wallart and Schaeffer have 

 given consistent descriptions of atresia foUiculi and the intersti- 

 tial cells of the human ovary. Wallart from an examination of 

 67 ovaries from fetal life (8 months) up to ninety-one years, 

 concluded that the interstitial cells (termed by him the inter- 

 stitial gland) are best developed and most closely massed during 

 early years (up to puberty). During sexual maturity they are 

 present but not so abundant, save during pregnancy. He rec- 

 ognized their origin from the theca interna of atretic follicles. 

 A greater amount of atresia during the period of pregnancy and 

 in the puerperium as indicated by the observations of Sinety, 

 Wallart, Seitz, Pinto and Fellner, would be expected a priori. 

 Whether or not the interstitial cells so formed should be regarded 

 as an internal secretory gland having peculiar relations to preg- 

 nancy is of course another question. The more follicles reach 

 maturity and rupture (forming corpora lutea) the less the de- 

 generation, hence the appearance of balance and vicarious de- 

 velopment that appealed to Aime, and Ancel and Bouin. From 

 my personal observation I may state the atretic follicles and 

 their lipoid-containing theca cells (interstitial cells) are easily 

 demonstrated in the human ovary by appropriate methods. 

 The latter are more insignificant than in the cat, and doubtless 

 relatively less persistent (as such) in the larger ovary. The 



