SUPPLEMENTARY NOTES ON TWINS IN CATTLE. 73 



given as proved by the large body of evidence accumulated by 

 Keller and Tandler and by myself. Esther Rickards and F. Wood 

 Jones (1918) find unconformable cases in goats described by 

 themselves and others and conclude that these " show the un- 

 soundness of Lillie's theories " : A pair of apparently female goat 

 kids turn out to be quite identically predominantly male in their 

 anatomy ; " it is affirmed of a celebrated he-goat ' that one season 

 every kid he sired, eleven in number, was a hermaphrodite 

 (quoted from Davies, 1913). Such cases imply a genetic founda- 

 tion which certainly deserves study and promises interesting re- 

 sults, but they obviously do not have any bearing at all on the 

 bovine free-martin. 



Keller and Tandler (1916) investigated the membranes in four 

 cases of triplets and two cases of twins in goats. In two of the 

 triplet cases three corpora lutea were found in each case, and in 

 one of the twin cases there were two corpora lutea. The ovaries 

 were not available in the other two cases. The chorions were 

 fused, but the individual foetal circulations were separate, as in 

 sheep (cf. Lillie, 1917)- The foetuses of four of these cases, 

 which included both sexes, were examined and found normal in 

 the anatomy of their reproductive organs. These findings thus 

 confirm, as far as they go, the idea that hermaphrodites in goats 

 are not usually a result of twinning as such; but they do not ex- 

 clude the possibility of the occasional occurrence of intersexual 

 conditions due to hormones. It is obvious that goats are not 

 favorable material for the investigation of the action of sex hor- 

 mones in foetal life. 



Hartman (1920) suggests that certain cases of hermaphroditism 

 in mammals may be interpreted as " reciprocals " of the free- 

 martin — that is, cases in which the male of a two-sexed pair is 

 modified in its sexual development by hormones of the female. 

 The evidence that he offers is of the slenderest description. More- 

 over, if, as seems probable, the female in mammals does not pro- 

 duce sex hormones during the early part of foetal life, the possi- 

 bility of " reciprocal " free-martins would seem to be excluded. 

 The source of the ovarian sex hormone is by no means so certainly 

 ascertained as that of the testicular hormone. The weight of 

 opinion inclines to the view that the cells of origin in the ovary are 



