526 GENCHO FUJIMURA 



appear, the lipoid granules first make their appearance as 

 their forerunners, and the former pass into the latter in suc- 

 cession, as has been entirely agreed upon by many observers. 



With regard to the origin of lipoid granules, the Zoyas 

 ('91) pointed out that there was a certain quantitative relation 

 between granules and plastosomes, and this fact was acknowl- 

 edged by Mulon, Athias, and Tsukaguchi, though Levi alone 

 tried to deny it, as in the case of external secretory granules. 



With regard to the secreting phenomena of luteal cells. Van 

 der Stricht argued that in the order Chiroptera it was possible 

 to divide them into two forms, viz., serous secretion and lipoid 

 secretion. By serous secretion is meant that the follicular 

 epithelium, being the antecedent of the luteal cells, secretes 

 liquor folliculi, and, according to him, the Graafian follicle, 

 after rupturing, still keeps on secreting in this manner for a 

 fixed period, it being characteristic of this secretion that in the 

 peripheral part of protoplasm of the young luteal cell some 

 serous infiltration appears, and for that reason gives that part 

 generally a somewhat transparent appearance. Already at this 

 period a large quantity of small lipoid granules appears within 

 the cell bodies ; however, since these granules do not as yet per- 

 form any functions, he called this stage the serous secreting 

 period of the luteal cells; then, as the ovum settles, the corpus 

 luteum has already reached its highest degree of development, 

 and he termed it the second stage of corpus luteum formation. 



At this stage the cell body is already filled with numberless 

 lipoid granules, which, undergoing a chemical change, cause the 

 cell body to keep on discharging secreted matter until the end 

 of pregnancy. This is what the lipoid secretion means. This 

 theory seems to have been afterward accepted in the main 

 also by Levi. However, the condition is entirely different in the 

 Rodentia, and especially in the rabbit. According to the obser- 

 vations of Cohn and Tsukaguchi, lipoids chiefly appear in a high 

 degree only in the early part of pregnancy, then disappear rather 

 speedily. In the second half of pregnancy the lipoids change 

 into vacuoles almost as transparent as water, the cell bodies pre- 

 sent a highly distinctive vacuolar structure, such condition being 



