THE CORPUS LUTEUM OF PREGNANCY IN SWINE. 85 



As to the lutein cell itself, the present findings, that the cells are apparently in a high 

 state of organization from early pregnancy to term, would seem to give some strength to 

 the contention that the corpus luteum has a function of importance in pregnancy. Empiri- 

 cally it has been shown clearly that extracts and powders of corpus luteum have a beneficial 

 effect in certain disturbances of the reproductive system in women (see Burnam (1912) 

 for full account and literature to date) ; and it has been found that extracts of corpus luteum 

 when injected into dogs promptly cause a lowering of the blood-pressure. None of those 

 who have worked in this field, so far as I know, have tried the effects of corpora lutea of 

 definite age. There is, however, certain evidence that the corpus luteum during the first 

 half of pregnancy has a different potency than in the second half, namely, the fact dis- 

 covered by Fraenkel (1903) and confirmed by Marshall and Jolly (1905), Niskoubina (1909), 

 Dick and Curtis (1912), and others, that extirpation of the corpus luteum during the first 

 half of pregnancy is almost invariably followed by abortion. This fact, which seems so 

 true for guinea-pigs and rabbits, has been flatly denied to hold good in animals by Daels 

 (1908), and for human patients by Essen-Moller (1904), Graefe (1905), Flatau (1907), and 

 Sokoloff (1913), while Puech and Vanverts (1913) propose the compromise statement 

 that the corpus luteum is useful in an accessory way, but not absolutely necessary to 

 the embedding and early development of the human embryo. Unfortunately for our 

 present discussion, the experiment has not been tried on sows, which are not convenient 

 laboratory animals. I agree with Cohn and Van der Stricht that the microscopic 

 appearance of the lutein cell seems to favor the theory of an internal secretion of the corpus 

 luteum, and I would add that the corpus luteum, while apparently in a high state of 

 activity from the beginning to the end of pregnancy, shows greatly different forms of cell- 

 structure in the earlier and later months. We may hope that this hint will be put to further 

 test by experiment and clinical observation. 



DISTINCTION BETWEEN THE CORPUS LUTEUM OF PREGNANCY AND OF OVULATION. 

 The history of the corpus luteum for 350 years has been a curious mingling of truth 

 and error. Discovered by Volcherus Coiter in 1573, the corpus luteum was thought by 

 Regner de Graaf to be an evidence of pregnancy or of previous child-bearing. Abernethy 

 and Sir Astley Cooper swore away the innocence of a dead woman in a court of law because 

 one of her ovaries was found at post-mortem to contain a corpus luteum. About the earlier 

 decades of the nineteenth century it became known that every ovulation is followed by the 

 formation of a corpus, and then arose the still unsettled discussion as to whether the corpus 

 luteum of ovulation can be distinguished from the corpus of pregnancy. Interesting 

 accounts of the earlier phases of this question are found in Dalton's Prize Essay of the 

 Philadelphia Academy of Sciences for 1851, and in Taylor's "Medical Jurisprudence." 

 Next the microscope was called to aid, with little effect. De Sin6ty (1877) believed the 

 two sorts of corpora to be exactly alike. The same statement is made by Ravano (1907). 

 Marshall (1910) sums up his opinion in the statement that the two kinds of corpora are in 

 the earlier stages identical, and otherwise essentially similar. Niskoubina (1909) thinks 

 that the corpora lutea of pregnancy of rabbits contain more fat than the corpora of ovula- 

 tion, but Fenger, working on the ovaries of cows, analyzed hundreds of corpora lutea, and 

 found the fat content equal (1914). Miller (1914), in the latest publication upon this 

 subject, holds that the corpora lutea of pregnancy (human) may be distinguished from those 

 of ovulation by the absence of fat-reaction, of colloid degeneration, and of deposition of 



