7 2 4 SCIENCE PROGRESS 



contains a large space filled with liquor folliculi and in some 

 cases a certain amount of extravasated blood. All parts of the 

 follicular wall now take part in the changes leading to the 

 formation of the fully grown corpus luteum. The membrana 

 propria is burst through in a large number of places by active 

 irruptions of the theca folliculi, which sends shoots of connective 

 tissue towards the centre. With these connective tissue 

 sprouts, new blood vessels enter the corpus luteum, and in 

 their immediate neighbourhood the membrana propria becomes 

 lost, although in other places it persists for some time. 

 Simultaneously with this invasion the cells of the membrana 

 granulosa gradually become transformed into lutein cells and 

 start to fill up the central cavity. 



On account of the ingrowths from the theca, the membrana 

 granulosa cells become divided up into groups, so that the young 

 corpus luteum presents a lobulated appearance. Very soon, 

 however, the irruptions burst through the membrana cells and 

 reach the central cavity, where they form ultimately a plug of 

 connective tissue. 



In the ripe follicle the epithelial cells are small and crowded 

 together as if under pressure. During the invasion of the thecal 

 ingrowths these cells undergo a great hypertrophy both of the 

 nucleus and the cell body and become much less tightly packed 

 together. Their cytoplasm also becomes more and more granu- 

 lar, the granules giving to the cells that intense yellow colour 

 so characteristic of this body, and the granulation, which be- 

 comes more marked as the formation proceeds, certainly sug- 

 gests a secretory activity on the part of the lutein cells. 



The matrix of the fully developed corpus luteum, then, 

 contains two distinct kinds of cells, the lutein cells and the con- 

 nective tissue network and central plug. Opinion is divided as 

 to the origin of both of these, and it will be convenient to deal 

 with each of them separately. 



With regard to the lutein cells two main theories have been 

 advanced. On the one hand, Von Baer in 1827 (22) suggested 

 that the entire corpus luteum was derived from connective tissue 

 and that the membrana granulosa took no part in its formation, 

 and was either discharged with the ovum or degenerated in situ. 

 On the other hand, Bischoff in 1842 (4) stated that the lutein cells 

 were formed by the hypertrophy of the cells of the membrana 

 granulosa and not from the theca, which only supplied the 



