INTERNAL SECRETION OF TESTICLE 167 



illustrate these quantitative relations by the following diagram 

 {Fig. 89). The quantities of the hormone secreted in the blood 

 are given on the abscissa; the intensity of the effects on the 

 ordinate. The normal development of the somatic sexual 

 characters, A^, seems to be brought about by a quantity of 

 hormone, q^, the threshold quantity which is smaller than that 

 normally secreted and entering the blood; the latter assumption 

 is supported by the fact that castration results do not appear 

 when small particles of the 

 testicle are present. When 

 the quantity of the hormone 

 is greater than q^, the hor- 

 monic effect is not increased, 

 and an excess of the quantity, 

 for instance, q2, will cause 

 only a temporarily increased 

 effect such as at the "heat." 

 Within the limits of and q^, 

 the intensity of the hormonic 

 effect might be proportional 

 to the quantity of the hor- 

 mone, beyond qi this pro- 

 portionality will not exist 

 excepting under certain 

 special conditions (heat, 

 pregnancy). Further, I sug- 

 gested that an excess in the 

 quantity of the hormone of 

 the sexual glands prior to 

 puberty might have an 

 accelerating effect on the 

 development of the somatic sexual characters and the 

 psycho-sexual behaviour, i.e., that this excess might cause a 

 pubertas praecox. Basing himself on his own experiments and 

 on observations of Houssay (1907) on fowls, Pezard (1918, 1919) 

 suggested that the relations between the hormonic quantity 

 and the hormonic effect may be somewhat different. Pezard 

 stated that not only did small quantities of testicular tissue 

 cause development of sexual characters, but that this develop- 

 ment was always a complete one, when a certain minimal quantity 

 of testicular tissue was present. When this minimal quantity is 



Fig. 89. — Diagram : Dependence of hor- 

 monic effect upon the quantity of tes- 

 ticular hormones. Abscissa: quantity 

 of hormone ; ordinates : hormonic 

 effect as expressed by somatic sex 

 characters e.g , length of comb). 

 ^1 — quantity of hormone sufficient 

 for normal hormonic effect {N). 

 q^ — quantity of hormone normally 

 present. It is assumed that there is 

 between o and q^ proportionality 

 between the quantity of hormone 

 and the hormonic effect, whereas no 

 such proportionaUty exists beyond 

 9i and q^. Further increase of the 

 quantity of hormone may tempo- 

 rarily cause an increase of the hor- 

 monic effect as during heat (as indi- 

 cated by dotted line) ; but this 

 increased hormonic effect does not 

 last. 



