SEXUAL HORMONES AND MORPHOGENESIS 477 



due to the fact that no more testicular secretion entered the 

 epididymis. 



The seminal vesicles of the guinea pig in my experiments 

 (1923) were always normally developed on both sides, although 

 a testicular fragment was present only on one side. It seems 

 clear that the dependence of the seminal vesicles upon the 

 testicle is an hormonic one ; it may be recalled that no testicular 

 secretion normally enters the seminal vesicles of the guinea pig. 

 Now contrary to what was the general rule, I twice saw under- 

 development of the seminal vesicle on the side on which the 



Fig. 138. — Unilateral underdevelopment of 

 seminal vesicles in case of unilateral 

 castration in guinea pig 6J months old 

 (Phot. Nr. 63). Nat. size. The right 

 testicle has been removed at an age 

 of 2 weeks; an upper fragment of the 

 left testicle has been left in the body. 

 The left vesicle is normal, the right 

 one underdeveloped. 



testicle was removed, once in a guinea pig (Fig. 138) and once 

 in a mouse after unilateral castration. I am unable to explain 

 this phenomenon. There were no adhesions which could 

 explain the underdevelopment. 



In view of all these observations I should hke to emphasize 

 the fact that the influence of the sex gland on the organism is 

 evidently not merely hormonic, but is of a much more manifold 

 nature (cf. Cramer in Marshall's The Physiology of Reproduction, 

 2nd edition, 1922). The greater the knowledge we possess 

 concerning the dependence of morphogenetic processes on the 

 sex gland, the more complicated the whole problem becomes, 

 and the greater are the difficulties to be surmounted. Many 

 apparently contradictory facts are probably due to the practice, 



