88 THE CORPUS LUTEUM OF PREGNANCY IN SWINE. 



Fellner (1909) believes that in the human ovary a few follicles may remain ripe or 

 become ripe during pregnancy. Ravano (1907) has taken the still more advanced stand- 

 point, based on the study of ovaries from 60 pregnant women who came to the operating 

 table or to post-mortem during pregnancy. He found many follicles "approaching ripe- 

 ness," and also thinks that he had three cases in which ovulation had occurred during 

 pregnancy. These were merely cases in which two corpora lutea were found without twin 

 pregnancy ; and the microscopical details given are so slight that I do not think these cases 

 are sufficient evidence on which to base such a statement as Ravano's that ovulation and 

 corpus luteum formation subsequent to that which gave rise to the fetus occur in 5 per cent 

 of all human pregnancies. In spite of these cases I retain the opinion that the rupture of a 

 Graafian follicle in an ovary containing a corpus luteum of pregnancy during term is an 

 extremely rare occurrence. Keller (1913) did not find a case in 24 human cases, Fellner 

 ( 1909) in 13 cases, nor Seitz (1905) in 36. Ruge (1913) studied 106 human ovaries without 

 finding a freshly ruptured follicle, and he thinks the presence of a recent corpus luteum 

 excludes the possibility of the rupture of a follicle. The case which I have to report seems 

 to be one of those classic exceptions which prove a rule. 



The uterus of specimen No. 70 contained three fetuses whose crown-rump length 

 measured 70 to 75 mm. The left ovary contained no corpora lutea; the right ovary con- 

 tained 8 prominent corpora lutea about 11 mm. in diameter and a number of follicles 

 measuring 5 mm. in diameter. Between one of the corpora lutea and one of the follicles 

 was found a body of ovoid shape about 2 by 2 by 3 mm. in size, which presented on its sur- 

 face a crater-like scar covered by a few tags of fibrin, resembling exactly the healing point 

 of rupture of an ordinary corpus luteum, but only about 0.5 mm. in diameter (fig. 19, a). 

 A section of this structure showed that it was indeed a recently ruptured follicle (fig. 20). 

 The granulosa was several layers thick, of normal appearance, and intact except at its 

 point of rupture, where it and also the theca were replaced by a recent scar. The granulosa 

 was rather wavy in contour (fig. 20, a), and beneath it lay the theca interna, thicker than 

 usual (fig. 20, b). If I interpret the appearance aright, neither layer showed signs of con- 

 version into lutein cells. I believe that this unusual specimen is due to an accidental 

 rupture of a Graafian follicle, probably by pressure between its neighboring growing follicle 

 and corpus luteum. 



ABNORMALITIES OF THE LUTEIN TISSUE. 



An interesting anomaly of the ovary is partial accessory lutein-cell formation, to which 

 attention was called by R. Meyer (1913) . This consists of the formation, during pregnancy, 

 of lutein cells in atretic follicles or even in ripe follicles, which in some human ovaries is 

 said to go so far that a full corpus luteum may be formed which is finally indistinguishable 

 from the true corpus luteum proper to the pregnancy, which is found in the same ovary or 

 its mate. This phenomenon, at least in its advanced state, must be very uncommon. In 

 the sow I have seen a case of what is apparently the same partial lutein formation in a 

 normal ripe follicle, not during pregnancy, but in the presence of a corpus luteum of 

 ovulation. 



The right ovary of specimen No. 136 contains 4 corpora lutea 5 mm. in diameter, which 

 appear on section to be young corpora lutea of ovulation. In addition there is a follicle 

 10 mm. in diameter, to be described. The left ovary contains 3 corpora similar in gross 

 appearance to those of the right ovary, except that one of them is slightly cystic. On 

 section of the large follicle in the right ovary, it is found that over almost the entire circum- 



