EFFECTS OF GONAD GRAFTS IN CHICKS 29 



Result: Left gonad nearly like a normal ovary; right gonad 

 does not resemble normal degenerating right ovary, but is more 

 or less Hke a male gonad; left gonad, 6 x 2.3 mm.; right gonad, 

 2.5 X 1 mm. Wolffian and mtillerian ducts of the female type. 



13. Embryo no. 44-16. Operated April 5, 1919. Piece of 

 ovary from young hen (five and one-half months old) grafted 

 on a ten-day-old embryo. Opened April 15th. Age of embryo, 

 20 days; duration of graft, 10 days. 



Result: Gonads of the female type, the right gonad larger 

 than normal; left gonad, 5.5 x 1.6 mm.; right gonad, 3 mm. 

 Wolffian and miillerian ducts of the female type, but the right 

 mtillerian duct better developed than in the normal female. 



14. Embryo no. 30-9. Experimental conditions the same as 

 in no. 30-6. Age of embryo, 19 days; duration of graft, 10 days. 

 The graft grew very well; its size, 6.5 x 7.0 mm. 



Result: Gonads of the female type in general, but smooth in 

 texture similar to testes; shape also similar to that of testes; 

 left gonad, 4.8 x 1.1 mm.; right gonad, 3.5 x 0.7 mm. Wolffian 

 and mtillerian ducts nearly as in the normal female. 



d. Summary of i7itersexual characters produced by gonad grafts. 

 The intersexual characters produced in chick embryos by the 

 implantation of grafts of gonad tissue upon their chorio-allantoic 

 membranes may now be summarized. 



1. In affected embryos having gonads of the male type, the 

 difference in length between the two gonads is greater than is 

 the case with normal testes. The difference between right and 

 left testes in normal embryos does not exceed 0.5 mm. (table 5). 

 In several intersexual embryos, however, the difference in length 

 of the two gonads exceeds 1 mm., and in extreme cases is stiU 

 greater, as 1.8 mm. in embryo no. 10-5, 1.9 mm. in embryo no. 

 17-1, and 2.3 mm. in embryo no. 15-5. This length difference 

 between the two gonads is abnormal for the male, but is char- 

 acteristic of the female, where the left ovary is much larger than 

 the right one. In this regard, then, the affected embryos may 

 be considered as intermediate between normal males and females. 



2. In several affected embryos, male-type gonads exist simul- 

 taneously with female-type mtillerian ducts. Examples of this 



