Chapter VI. 



The Sex Specific Action of the Testicular 

 and Ovarian Hormones. 



Hitherto in the present work we have refrained from discussing 

 the important question as to the sex specific action of the 

 testicular and ovarian hormones. Yet we have tacitly 

 assumed that the hormones have a sex specific action, since we 

 concluded from the castration experiments that the soma is 

 asexual during embryonic life, and that it does not develop sex 

 characters before the gonad is differentiated. But we have 

 not yet presented any incontestable argument in support of the 

 view that there is a sex specifity for the respective hormones. 

 This question has been investigated by various authors, 

 and in this chapter we shall deal with their experiments. 



A. EXPERIMENTS ON AMPHIBIANS. 



Steinach (1910) injected into castrated male frogs triturated 

 ovaries of females on heat. He stated that the clasp reflex is 

 evoked by this stimulus in just the same way as it is by injecting 

 testes. However, by injecting ovary the reflex is not so fully 

 e vocable, and the experiment is not so regularly successful as 

 when testicular substance is employed. Harms (1910) and 

 Meisenheimer (19 12) also found that the clasp reflex in 

 castrated male frogs may return after injection of ovary. 

 Relying on these experiments, we may suppose that hormones 

 are formed also in the ovary, which may thus condition the 

 oestral phenomena in the male. 



Meisenheimer has studied carefully the behaviour of the 

 thumb pad in male frogs after introduction of ovarian sub- 

 stance, the ovaries having been put into the dorsal lymphatic 

 sac. By so doing the growth of the pad was induced, and an 

 hypertrophy of the epithehum and the glands was brought 

 about. The pad of the castrated male injected with ovary is 



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