82 B. F. KINGSBURY 



the organism, the study of the origin of the interstitial cells in- 

 dicates clearly that considerable hesitancy should be observed 

 in declaring them specific glandular elements. 



The corpus luteum and the corpus atreticum have been re- 

 peatedly compared, and despite marked differences there ap- 

 pears to be much fundamental resemblance. Both express es- 

 sentially reactions of degeneration. In both relatively large 

 amounts of lipoid appear in their cells attended by the presence 

 of lipochrome. In the one it is the follicle cells that apparently 

 undergo hypertrophy — although this is still a disputed point, 

 and it is easily conceivable that the process may differ in differ- 

 ent forms. In the other the cells of the theca alone hypertrophy 

 and become charged with lipoid. The older describers of the 

 corpus atreticum compared it with the corpus luteum — some- 

 times perhaps confused the two — or described intermediate forms 

 (Schulin '81). Bouin and Ancel have more recently revived the 

 comparison, placing it on the modern 'functional' basis of the 

 internal secretions. The mammals are divided by them into 

 two groups: those in which ovulation is spontaneous, at definite 

 periods, and those in which it occurs at coitus. Those of the 

 first group possess, accordingly, two varieties of corpus luteum, 

 a corpus luteum periodicum (menstruationis), and a corpus 

 luteum gestativum (gra\dditatis), w^hile the forms of the second 

 division have but the last kind of corpus luteum. These forms 

 possess, however, an 'interstitial gland' which takes the place of 

 the corpus luteum periodicum and is not present in those mam- 

 mals which possess the two varieties of corpus luteum, among 

 which Bouin and Ancel include man, dog, cow, mare, sow. Both 

 classes have thus two kinds of internal secretory gland; the first 

 associated with the uterine changes at pregnancy, the second 

 subserves other forms of ovarian influence. 



While there may be an ultimate significance in the compari- 

 son of corpus luteum and corpus atreticum, on the morphologi- 

 cal side this particular comparison fails, if for no other reason, 

 because in one member of the forms of the first group (man), 

 interstitial cells are present, and in the other forms it is quite 

 clear that corpora atretica occur and differ in no fundamental 



