560 SWALE VINCENT 



moses of thfcir processes. Their nuclei closely resemble those of the 

 capillary walls. The connective tissue of the central plug consists of 

 stellate elements. In some animals the fully formed luteal cells are 

 rounded or spindle shaped and may show signs of degeneration. 



The luteal cells are, in all probability, derived from the follicular 

 elements. The glandular nature of the organ is admirably shown in the 

 corpus luteum of Dasyurus (see Figs. 1 and 2). 



Chemistry of the Corpus Luteum and Physiological 

 Action of Extracts 



The only substances which are recognized as characteristic of the ovary 

 and corpus luteum belong to the group known as lipochromes. It is not 

 known how far the individual lipochromes are peculiar to the organs 

 in question. Closely allied substances are certainly found in other organs 

 and tissues. The yellow pigments found in animal tissues are related 

 to the similarly colored vegetable pigments. Willstatter and Escher have 

 studied the lutein obtained from egg yolk. The molecular weight was 

 found to be 624, and the formula given is C 40 H 5r) O 2 . It is isomeric with 

 xanthophyl, which may be obtained as a by-product in the preparation 

 of pure chlorophyl. It has been stated that lutein is an oxidation product 

 of carotin (obtained from carrots), but this is denied by Serono, who be- 

 lieves that lutein is an oxidation product of the esters of cholesterol with 

 unsaturated acids. 



An attempt to isolate the active principles of ovary and corpus luteum 

 has been made by Iscovesco. This writer devised a laborious method of 

 isolation, depending on solubility in different media. One of the sub- 

 stances he claims to have isolated he calls "ILF.b.," as an ether extract 

 of desiccated ovary. It is soluble in acetone. The other substance 

 ("V.D.c.") is alcohol soluble. 



Hermann believes that he has succeeded in isolating the active prin- 

 ciple of the corpus luteum and of the placenta. 



Morley calls attention to the need for more uniform methods in the 

 preparation of extracts. Within the last few years several observers have 

 investigated the influence of extracts of corpus luteum upon the contrac- 

 tions of the uterus and smooth muscular fibers in other places. Stickel 

 reports that parturition in the rabbit is accelerated by injection of extracts 

 of corpus luteum. Guggisberg, on the contrary, obtained inhibition of 

 uterine contractions. 



Itagaki states that extracts of corpus luteum generally produce a dis- 

 tinct increase of ton in the surviving uterus of the rat, rabbit, dog, and 

 guinea pig, though occasionally the opposite effect is brought about. The 

 different results are due to the effects of two separate principles, having 



