Gatenby — Notes on the Human Ovary. 73 



examination of the literature it appears that there is a considerable division 

 of opinion on the subject, and it is evident that differences between the two, 

 excepting that of duration, are often difficult to demonstrate by ordinary 

 examination of fixed material. 



Corner claims that he can not only distinguish the corpus luteum of 

 pregnancy from that of menstruation, but that he can distinguish seven clear 

 periods in the history of the corpus of pregnancy. His periods are as follows : — 



1. Preparatory. 



2. Exoplasmic development, 1st part. 



3. Do. do. 2nd part. 



4. Transition period. 



5. Endoplasmic development, 1st part. 



6. Do. do. 2nd part. 



7. Beginning of retrogression. 



He says : " The corpus luteum, being an organic body, presents considerable 

 variety of structure, so that these periods overlap, and pass gradually into 



each other " So far as the granules within the luteal cells are concerned, 



Corner mentions that in period 1, there is practically no endoplasm on account 

 of the large numerous exoplasmic vacuoles which exist in the luteal cells, 

 while fat granules are present in great quantity. In period 2, the luteal cells 

 are similar, but the distiibution of fat is more general. In period 3, the 

 endoplasmic area around the nucleus is now clearly developed. In period 4, 

 the ring-like vacuoles of the exoplasm have nearly disappeared, and tlie 

 entire cell becomes gradually occupied by homogeneous cytoplasm. 



In the fifth period, or that of endoplasmic development, one gets an 

 increase in the diversity of the cells. Many cells show peripheral 

 canalization, while neighbouring cells may be quite free from such 

 protoplasmic differentiations. The additional cells of Corner are now best 

 developed. In the later stages of the life history of the luteal cells, one or 

 more fat globules much larger than any before noted make their appearance. 



From this short account of Corner's work it will be noted that this author, 

 following Cesa-Bianchi, depends principally on what may roughly be called 

 exoplasmic and endoplasmic ax-eas of the lutein cells. Unlike Van der Stricht, 

 this author does not try to describe serous and lipoid periods of secretion. 



How far the endoplasmic area of Cesa-Bianchi and Corner is traceable to 

 the change in position, growth, and spreading out of the Golgi elements, has 

 yet to be ascertained. But there is good reason for believing that some of 

 the elongate spaces drawn by Corner are the unstained " ghosts " of the Golgi 



