PHYSIOLOGY, CHEMISTRY AND PATHOLOGY 451 



suppression of the ovarian cortex and hypertrophy of the homologues of 

 the seminiferous tubules (Chapin). The general appearance of the adult 

 free-martin is intermediate between that of the male and female, re- 



Fig. 11. Urogenital system of sterile free-martin 27 cm. long. X 4 /3. From two 

 sexed pair 14. Although this case is beyond the stage in which the testes of the male 

 normally enter the saccus vaginalis, the rudimentary ovaries are here in the body 

 cavity. In this case there appear to be rudiments of the cornua uteri. 1, rectum; 2, 

 gonad; 3, cornua uteri; 4, urogenital sinus; 5, umbilical artery. (Lillie, 1917, Fig. 

 26, p. 448.) 



sembling the ox or spayed heifer. The twin bull, on the other hand, is 

 normal and fertile (Fig. 12). The free-martin condition is found only in 

 association with a male twin the chorion of which has formed vascular an- 

 astomosis with the chorion of the female. Hence, the presence of a male 



