THE REPRODUCTIVE ORGANS 73 



^ has now been accumulated that the absence of the functional 

 testis brings about abnormal growth of bony tissues. But this, 

 according to modern views, is not due to the fact that the 

 testis is not acting as an organ of reproduction, but to the fact 

 that the normal internal secretion from the organ is not avail- 

 able for the controlling of the growth of bone in the body. 



Poncet in 1897 reported a series of experiments upon rabbits, 

 in which he found that castration has a very definite effect upon 

 the development of the skeleton. The bones of the castrated 

 ' animals were stronger, but especially longer, than those of the 

 controls. The increase in length was particularly noticeable 

 in the femur, the tibia, and the fibula. The whole skeleton of 

 the castrated rabbit was, however, somewhat larger than that 

 of the control. The fact that the presence of a functional 

 testis is inimical to bone growth is also emphasized by Lortet 

 and by Pirsche. The work of Pirsche firmly established the 



^ fact that castration in youth is followed by abnormal growth 

 of the long bones. Geddes has recently reinvestigated several 

 points in connection with the matter. He reports that males 

 whose testicles are functionless are found to possess unduly 

 long limbs. This undue length affects the radius and tibia 

 more than the humerus and the femur. The process of 



+~ ossification is unduly prolonged. He finds, also, that in animals 

 which have been castrated there is an increase in the length 



^ and weight of the bones, and a delay in the obliteration of the 



^epiphysial cartilages. In eunuchs there is delay in the com- 

 pletion of the process of endochondral ossification. Further, 

 the long bones of the appendicular skeleton are unduly long. 

 This excess of length is particularly remarkable in the more 

 distal segments of the limbs. The bones are thin, smooth, and 

 slender. Geddes is inclined to look upon these results as 

 occasioned by the setting free for general use of foodstuffs 

 which would otherwise have been used to provide for the drain 

 of sperm atogenesis. In other words, the activity of the sexual 

 glands is opposed to body- growth. Apparently there are no 

 experiments to determine whether simple vasotomy or ligature 

 of the cord itself will induce these bony changes. If simply 

 abolishing the spermatogenesis will bring about these changes, 

 it is obvious that the theory of internal secretion would have 

 to be abandoned. 



Loisel believes that one of the functions of the internal 



