SECONDARY SEXUAL CHARACTERS. 45 



this point of view. In the first of these two papers Lillie gives a 

 detailed account of the anatomy of the internal and external 

 genital organs in freemartins in various stages of embryonic 

 development and of his interpretation of the cause of the abnor- 

 malities and in the second paper Chapin describes the micro- 

 scopical findings in these cases. It follows from Lillie's observa- 

 tions and analysis that the sterile freemartin represents an indi- 

 vidual which was originally a female, but in which under the 

 influence of hormones carried into her circulation from the chor- 

 ionic vessels of a male twin, the female characteristics were more 

 or less suppressed and male characters acquired. This not only 

 applies to the secondary sexual characters, but even to the struc- 

 ture of the gonads. As Chapin has shown, the development of 

 the ovarian cortex and of ovarian follicles is more or less inter- 

 fered with or may be altogether suppressed, and the medullary 

 sex cords develop often in a way similar to the seminiferous 

 tubules, although spermatocytes or spermatozoa to not seem to 

 be produced. The development of the Miillerian ducts is like- 

 wise interfered with and seminal vesicles may develop instead. 

 The external genitalia and the mammary gland are least affected 

 by the male forming substances, which according to Lillie origi- 

 nated in the testicle of the male twin and were from here trans- 

 mitted to the female twin; these latter organs remain usually 

 female in character. 



These important findings may have some bearing on the 

 interpretation of our observation. There exist undoubtedly 

 marked similarities between the condition found in the freemar- 

 tins and in the condition of the genital organs of the guinea pig 

 which we examined. However, while Lillie and Chapin examined 

 embryological material, we have to deal with an adult animal. 1 

 In our case we observed a gonad which shows the characteristics 

 found in testicles under various pathological conditions. Similar 

 changes have been produced in testicles experimentally under 

 the influence of Roentgen rays. The tubules, the character of 

 the cells composing them and particularly of the nuclei closely 

 resemble structures which we found after transplantation of 



1 Microscopic sections through the gonads of an older freemartin from the ma- 

 terial of Dr. Lillie show a great similarity with our sections through the gonads 

 of the guinea pig. 



