466 EXPERIMENT STATION RECORD. [Vol.40 



ANIMAL PRODUCTION. 



The freemartiu: A study of the action of sex hermones in the fetal life of 

 cattle, F. R. Lilue {Jour. Expt. Zool, 23 (1917). No. 2, pp. S71-.' f 52. fog. 89).— 

 In this paper the author describes the gross anatomy of freemartins and the 

 vascular connections of twin cattle fetuses, and amplifies his previous conclu- 

 sions (E. S. R., 35, p. 169) that the sterile freemartin is fundamentally a female 

 modified by the sex hormones of the male twin. These, it is shown, are free 

 to circulate in both individuals during fetal life owing to secondary fusions of 

 the chorion and temporary union of the vascular systems. The study is baaed 

 upon the examination of 55 twin pregnancies secured from a slaughterhouse and 

 2 freemartins slaughtered after birth. In only two of the uteri examined were 

 the fetuses Inclosed in separate chorions. The existence of joint circulation 

 was continued in a number of cases by injections. 



In the L'2 cases, where both ovaries were attached to the specimen, each ovary 

 contained a corpus luteum. A cumber of gravid uteri containing only one fetus 

 were also collected. In the 46 eases where both ovaries had hen preserved, 

 only one ovary in each case showed a corpus luteum. These facts are held to 

 show, as far as they K'>, that most, If not all, twin pregnancies in cattle are 

 the result of ovulation in both ovaries, and consequently can not l.e attributed 

 to the partition <>f single eggs, a- had been assumed provisionally by Oole 

 (B. S. R., 3.",. p. 168) and Oth 



of the 55 pairs of fetal twins. 19 were both males, 11 both females, "Jl (-.in- 

 sisted of a male and a freemartin, 3 of a male and an anatomically normal 

 female, and 1 was too young to permit the determination of the s Two of 



the pairs of male and female were secured early in the Investigation before the 



system <>f note-taking had been perfected, in each there was a very narrow 

 connection between the chorions, bul no record was made as to whether the 

 connection was vascular. In the third case organic connection with the two 

 chorions was entirely lacking. In the other case of entirely separate chorions 

 the tWtD8 were both feina 



In discussing the reasons why this sort of embryonic sterilization Is not more 

 common in mammals, the author points out that chorionic foslon COUld only 

 occur in cases of diffuse placentation and that there are other quite special con- 

 ditions. "Such conditions are found only in normally uniparous ongulal 

 in whlcb the ovum grows to an extreme length very rapidly, BO that the a 



elated ova n t at an early stau r e which favors their organic union. Even then 



vascular anastomosis is not likely to occur to any considerable extent null 



the development of the fetal cotyledons is relatively late, so as to be preceded 

 by a condition of general vascularization of the chorion, before the highly spe- 

 cialized circulation of the cotyledons becomes dominant. Such is the condition 

 in cattle." The author suggests that the early development of the civic.! 

 in sheep may explain why freemartins do not occur in this form. 



A microscopic study of the reproductive system of fetal freemartins, 

 Catiiakim: ].. I'n.vi'iN (JOttT. Expt. Zool., 23 [1917), •' i s ~. / 



16). — A histological examination of the embryologlcal material collected by 



Lillie (see above) showed that the interstitial cells of the testis, whos< 



tion almost certainly determines the production of secondary sexual characi 

 are produced earlier in fetal life than the cells of the ovary having a Correspond- 

 ing function. In the case of twins Joint circulation is get up at a period which, 

 if the sexes are opposite, permits the male hormones to pass into the circulation 

 of the female in time to interfere with the development of the mechanism for 

 the formation of many of the female secondary m xual characters. Thercf. 



