48 LEO LOEB. 



Typical interstitial cells are absent in the normal ovary of the 

 guinea pig. If we should assume the gonads in this guinea pig 

 to be female our own observation would constitute a decisive 

 proof that also in the female guinea pig the interstitial cells 

 produce the substance which is responsible for the sexual desire 

 a conclusion which, however, as we stated above, would be con- 

 tradictory to other facts which we established previously. 



The case which we described may be compared to a single 

 equation communicated by nature, in which two variables are 

 present. While one equation is not sufficient to determine the 

 unknown factors in such a case, the variables have at least been 

 carefully denned in our case. We may hope that later a second 

 equation will be found which will permit denning all the variables. 

 We thought it therefore of interest that these observations should 

 be published. 



discussion that it is the so-called interstitial gland of the testicle which is responsible 

 for the development of the secondary sexual characters and of sexual desire in the 

 male. We wish, however, to emphasize the fact that in our case epithelial elements 

 were present in the testicle in addition to the interstitial gland and apriori we can- 

 not exclude the possibility that they and not the interstitial gland are the causative 

 agency in determining sexual phenomena. We are likewise not certain that this 

 can be excluded in those experimental and pathological conditions in which the 

 changes were attributed to the interstitial gland. However we are not directly 

 concerned with this question and W 7 e are not in a position to contribute definite 

 data which would favor or contradict this view. We wish, however, to reiterate 

 the fact that on various occasions we made observations which do not seem to 

 accord with the assumption that in the ovary the so-called interstitial gland initiates 

 heat. 



