COMPENSATORY HYPERTROPHY OF THE TESTES IN 



BROWN LEGHORNS. 1 



L. V. DOMM AND MARY JUHN. 



I. INTRODUCTION. 



Compensatory hypertrophy of the surviving testis after uni- 

 lateral castration was observed as early as 1890 by Ribbert (i). 

 Ribbert worked on mammalian material, using young but almost 

 mature rabbits. Ribbert removed the right or the left testis and 

 then compared the surviving gland with controls of the same 

 age after three months; considerable hypertrophy was almost 

 always found. The hypertrophied testis weighed six times as 

 much as one control gland in three cases. There was no differ- 

 ence in the degree of hypertrophy between the right or the left 

 testis. If the operated animal did not increase in weight as 

 much as did the normal controls, then the retained gland also 

 showed a corresponding lack of development. 



Lipschiitz '22 (2) repeated these experiments of Ribbert, 

 using also rabbit material for his experiments. It appears to 

 follow from Lipschiitz's paper that there is a compensatory 

 increase in weight of the surviving testis after unilateral castra- 

 tion when the operation is performed on young rabbits. This 

 increase in size and weight becomes progressively less the longer 

 the operated animals are kept ; about one year after the operation 

 there is not much difference in the weight of the surviving testis 

 and in that of one of the control pair of glands. Unilateral 

 castration is not followed by a significant increase in the size of 

 the remaining testis when the gonad is removed in adult rabbits. 

 Lipschiitz believes that his results indicate that the testis is 

 incapable of true compensatory hypertrophy ; the actual increase 

 in weight observed being due only to a more rapid rate of growth 

 of the isolated gonad. 



1 From the Whitman Laboratory of Experimental Zoology of The University of 

 Chicago. The expenses of this investigation were supported in part by the 

 Committee for Research in Problems of Sex of the National Research Council; 

 grant administered by F. R. Lillie. 



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