THE RELATIONS BETWEEN THE INTERSTITIAL 

 GLAND OF THE TESTICLE, SEMINIFEROUS TU- 

 BULES AND THE SECONDARY SEXUAL 

 CHARACTERS. 1 



LEO LOEB. 



The following observations may prove of interest in the analy- 

 sis of the relations between male gonads and secondary sexual 

 characters. 



While, as is often the case, an experiment of nature, unaided 

 by experiments in the laboratory, is unable to give a definite 

 answer to the questions which it raises, yet it would at present be 

 impossible to duplicate at will in the laboratory an experiment 

 such as we observed and it is, therefore, desirable that it should 

 be recorded. 



Our observations were as follows : 



Guinea pig No. 1523 had been sent to our laboratory by an 

 animal breeder as a female that had apparently been in heat, but 

 in some respects behaved abnormally. The report of the breeder 

 was as follows : 



'The female through her actions gave every sign of being in 

 heat; but upon examining her, she did not look to me as if she 

 really was in heat. I had her with two other females and she 

 would mount them just the same as a male guinea pig would do 

 when in the act of copulation and she would also allow the other 

 females to act in the same way. She would stand in this posi- 

 tion, meanwhile expanding the vagina, which generally is a sure 

 sign of their being in heat. I would say that she is with young ; 

 at least she should be pregnant, because she had been with a male 

 for some time. Expect some young at any time." 



The breeder made his observations July 8, 1917. On July 12, 

 1917, the animal, which weighed 615 grams, was prepared for 

 operation. Under ether anesthesia lumbar incisions were made, 



1 From the Department of Comparative Pathology, Wshhington University 

 Medical School, St. Louis, Mo. 



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