COMPENSATORY HYPERTROPHY OF THE TESTES. 471 



hypertrophy was shorter in our cases than in those reported by 

 Benoit and it is possible that the explanation for the different 

 results obtained may be found in this fact. 



The problem of compensatory hypertrophy of the gonad 

 presents its teleological as well as its physiological aspects. 

 The term itself has teleological implications; from this point of 

 view the "purpose" might be either to provide increased repro- 

 ductive capacity, which appears unnecessary, or to establish a 

 balance of hormones. There again the solution is unsatisfactory 

 for less than one testis is sufficient for maintenance of sex 

 characters as shown by Pezard, '21 (8); '25 (9); Champy, 



'25 (10). 



Physiologically considered it would appear to be obvious that 

 the growth of testis tissue is balanced against something else in 

 the organism. 



The general bodily metabolism favors the growth of a definite 

 amount of gonad tissue and no more. The removal of one testis 

 of a pair leaves a balance of conditions favorable to the con- 

 tinued growth beyond its normal size of the surviving member 

 which thereupon responds in proportion to its growth capacity 

 up to the limits of the favorable metabolism. When unilateral 

 castration is performed very early this may result in a single 

 testis greater in weight than a normal pair (Table I., case 16, 

 Table II., case 815), whether there may be a progressive limitation 

 of capacity for compensatory growth with increasing age as 

 maintained by Benoit is still an open question as far as our own 

 results are concerned. 



No theory is put forth in explanation of the change in the 

 reaction between gonad and organism which follows removal of 

 one of the gonad pair; it is shown by the facts. But the im- 

 portance of the principle appears again in the transformations of 

 the female following ovariotomy. The right rudimentary gonad 

 responds with a proliferation of the kind of tissue of which it is 

 composed at the time the demand on it is created, thus producing 

 the various types of right compensatory growth described in 

 completely and incompletely castrated hens by Domm, '24 (n); 

 '27 (12). The principle of compensatory hypertrophy is also 



illustrated in the growth of grafts. 

 31 



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