112 INTRODUCTION TO SENUAL PHYSIOLOGY 



Voronoii', and otliers have performed the same operation with 

 various modifications in metliod (in some instances the grafts 

 being obtained from animals), and satisfactory results have been 

 claimed. Further, the grafting of testicles obtained from ajjes 

 (the so-called " monkey glands ") has been practised with apparent 

 success by Voronoff and Thorek, and sections of the transplanted 

 organs have subse(}uently been made, showing that the testicidar 

 tissue had, in part at least, been preserved over periods of several 

 months. 



According to Steinach, rejuvenation can also be brouglit 

 about by vasectomy or ligaturing of the vas deferens, operations 

 which result sooner or later in the atrophy of the spermatogenetic 

 tissue without interfering with the interstitial tissue. It is not 

 clearly understood why the spermatogenetic tissue should be 

 destroyed as a consequence of the o])eration, and the results 

 obtained by various observers are by no means uniform. Thus 

 in testicular grafts in fowls spermatogenesis is known to continue 

 for some time at any rate after the transplanted organ has become 

 attached and without there being any exit for the seminiferous 

 fluid or spermatozoa. There can be no doubt, however, as already 

 mentioned, that vasectomy does frequently, if not usually, result 

 in cessation in the production of the spermatozoa, and sooner or 

 later in the degeneration of the seminiferous tubules. Steinach 

 goes further and states that as a consequence of the changed 

 conditions in the testis the interstitial tissue undergoes hyper- 

 trophy, and the resulting rejuvenation of the organism is attributed 

 to this hypertrophy on the part of the puberty gland. The 

 operation has been done upon aged men, both bilaterally and 

 unilaterally, and is stated to have been followed by favourable 

 results. The advantage of the unilateral operation is that one 

 testis remains fully functional. Steinach has also claimed to 

 have obtained successful results in rej uvenating rats by vasectomy, 

 and Sand has recorded similar results with dogs. A number of 

 other surgeons, both European and American, claim to have 

 brought about rejuvenation and other beneficial effects in men, 

 both by vasectomy and by grafting. 



A possible fallacy underlying this type of experiment is that 

 the result of any nutritional or environmental influence is not 

 easy to determine and may be neglected, while control experi- 

 ments are not always easy. Moreover, with operated men it is 



