EFFECTS OF GONAD GRAFTS IN CHICKS 23 



eight-day embryo. Opened August 1st. Grafts growing, but 

 small. Age of embryo, 21 days; duration of graft, 13 days. 



Result: Gonads of the male type, the left one 3.5x1.1 mm., 

 the right one 3x1 mm. They have, however, an abnormal 

 position on the wolffian bodies; instead of being parallel to the 

 median sagittal axis, they are inclined 50 to 60 degrees to it. 

 Wolffian ducts small, of the female type. Both miillerian ducts 

 present, and both with slight posterior differentiation as a uterus. 

 This embryo has male-like gonads, but female type ducts. 



4. Embryo no. 43-3 (fig. 16). Operated March 14, 1919. 

 Piece of testis about 1 mm. square from a chick thirty-six days 

 old implanted on an embryo of six days. Opened for examination 

 March 29th. Graft showed good growth. Age of embryo, 21 

 days; duration of graft, 15 days. 



Result: Gonads of the male type; left one 3.5 mm. long; right 

 5.7 mm.; anterior two-fifths of the left gonad pigmented. Wolf- 

 fian ducts rather of the male type; miillerian ducts present on 

 both sides and exhibiting only slight expansion of their posterior 

 portions. 



5. Embryo no. 27-5 (fig. 17). Conditions of the experiment 

 same as under embryo no 27-6. 



Result: Gonads of the male type; left, 3.7x1.4 mm.; right, 

 3 X 1.3 mm. Wolffian ducts of the male type. Anterior portions 

 of the miillerian ducts present; posterior two-fifths of their 

 courses degenerating on both sides. Such persistence of the 

 anterior portions, and the shape of posterior portions (although 

 they are retrogressing) show female rather than male charac- 

 teristics, or at least indicate an original development in the female 

 direction later inhibited. 



6. Embryo no. 28-8. Operated May 18, 1918. The right 

 testis of a chick embryo one week old was grafted on an embryo 

 of eleven days. Opened May 27th. Age of embrj^o, 20 days; 

 duration of graft, 9 days. 



Result: Gonads of the male type; left 4.5x1.1 mm.; right, 

 3.5 X 1.3 mm. Wolffian ducts of the male type. The miillerian 

 ducts have degenerated, leaving slender thread-like remnants 

 along their original courses. As a whole this embryo is more 



