THE STRUCTURE OF FREE-MARTIN GONADS 113 



moth. Goldschmidt ('17), in comparing the hormonic inter- 

 sexuaUty of the free-martin with the zygotical intersexuahty of 

 Lymantria, attempts to point out that the direction of sexual 

 differentiation changes at the time when specific sex-determining 

 hormones can act. In the free-martin he supposes that specific 

 sex-determining hormones arise in the interstitial cells, and act 

 the moment they enter the blood of the female, while in Lymantria 

 they arise from every single cell of the body. 



Among mammals in general an intersexual condition of the 

 gonad is somewhat rare. As a rule, in the cases that have been 

 examined, the gonad is usually part ovary and part testis (Pick, 

 '14). Gudernatsch ('11) points out that hermaphroditism in 

 the sense of separate ovaries and testes has not been demon- 

 strated in man or even in other mammals beyond a doubt. 

 Furthermore, in no case does the testicular part bear any stage 

 of male germ cells, but the ovarian part may produce germ cells 

 which are at least structurally normal. The possibility of the 

 formation of such intersexual gonads in mammals by the action 

 of sex hormones is suggested by Lillie ('17). This possibility 

 is made still stronger by the study of one of the free-martin gonads 

 (caseH-42). This gonad is partly ovary and partly testis. The 

 ovarian part contains distinct follicles with germ cells which are 

 apparently normal, while the testicular part contains typical 

 seminiferous tubules, but the germ cells are absent. Magnusson 

 ('18), reports free-martin gonads which have a similar structure 

 with the exception that the primary follicles lack germ cells. 

 This ovarian part, which is apparently an exceptional condition 

 in the free-martin gonad, probably arises either as a consequence 

 of a late introduction or of a temporary action of the male sex 

 hormones. In the former the cords of Pfliiger invaginate to a 

 slight extent, while in the latter alternative the ovary was only 

 partly transformed into a testis. Since the intersexual condition 

 of the free-martin gonad (case H-42) resembles the intersexual 

 conditions of the gonads of other mammals, it appears that they 

 may have an interpretation in common. It thus follows that in 

 all mammals where there is a possibihty of embryonic anas- 

 tomosis of the blood-vessels between individuals of opposite sexes, 



