SOME POINTS OF GENETIC INTEREST IN 

 REGENERATION OF THE TESTIS AFTER 

 EXPERIMENTAL ORCHECTOMY IN BIRDS. 



By C. J. BOND. 



In 1906 I published some observations on the result of unilateral 

 oophorectoni}' in Rabbits (see " Inquiry into some points in uterine 

 and ovarian physiology and pathology in Rabbits," B. M. J., July 21st, 

 1906). In this communication it was shown, among other results, that 

 the removal of one ovary in the female Rabbit is followed by a com- 

 pensatory overgrowth in the remaining ovary, and further that this 

 hypertrophy affects both the Graafian follicles or ova-bearing cells and 

 the internal secretion-forming cells. 



At this point it seemed desirable to ascertain whether the same 

 process occurs in the remaining testis after unilateral orchectomy. 



This was found to be the case in Birds but during this experimental 

 investigation' some further facts were elucidated which seem to me to 

 have some important genetic interest. 



In the first place it was found in both male Fowls and Pigeons 

 that when one or both testes were removed intracapsularlj-, that is to 

 say when the testicular substance had been apparently wholly removed 

 and the capsule alone left, a regeneration of the secreting tissue of the 

 testis and the tubuli seminiferi took place within the capsule so 

 evacuated. 



In a certain period of time, varying from six weeks to six months, 

 the whole substance of the normal-sized testis may be thus restored. 

 Fig. 1 shows the naked-eye view of two testes so regenerated in each 

 of two cockerels, in one case (22 c.) after six months and in another 

 (20 c.) after seven months. PL IV, fig. 2 shows a transverse section of 



' The actual operations connected with this investigation were kindly performed for 

 me by Sir V. Horsley, F.R.S., at University College, London. 



