REPRODUCTION AND SEX 501 



been incorporated in the heredity-bundle. As we do not maintain that 

 Nature works in this direct way, our suggestion is that such measure 

 of congruence as there is in, say, mascuHne sex-characters (e.g. 

 brighter colouring, exuberant decoration, smaller size) may be hypo- 

 thetically interpreted as due to their having arisen as germinal varia- 

 tions or mutations in germ-cells predetermined to develop into males. 

 As a subsidiary hypothesis, we suggest that augmentations of the 

 acti\'ity of the gonadial glands (due either to germinal or to nurtural 

 causes) may have from time to time set free in the organism an 

 unusual abundance of hormones with a corresponding exaggeration 

 of individual sex-characters. To those who are Weismannists by 

 conviction, yet having a suspicion that there must be something in 

 Lamarckism after all, we suggest for critical consideration the 

 hypothesis that this unusual abundance of hormones (of the nature 

 of which very little is known) may exert an influence on the germ- 

 cells in the gonads and stimulate in them the determinants corre- 

 sponding to the secondary sex-characters which are being especially 

 stimulated in the parental body in question. 



SEX-CHARACTERS IN INDIVIDUAL DEVELOPMENT.— We 



can imagine that what obtains in ontogeny is somewhat as follows. 

 The fertilised egg-cell, in a way inconceivable to us, is the vehicle 

 of the determinants (or factors, initiatives, potentialities or genes!) 

 of all the characters proper to the species. It also contains the 

 possibiUty of giving rise to the characters peculiar to either sex, 

 whether of the essential sex organs, or of the subsidiary sex organs, 

 or of distant parts of the body. It is probable that whatever deter- 

 mines whether the fertilised eg^ is to develop into a sperm-producer 

 or an egg-producer determines at the same time that it shall develop 

 the masculine or the feminine set of characters. The cause which 

 determines that the fertilised ovum is going to develop into a deer 

 with testes, also determines that it is going to develop into a deer 

 with antlers. 



We may compare the determinants of sex-characters to seeds 

 which will not germinate except in particular kinds of soil. The 

 determination of sex settles the question of (protoplasmic) soil. If 

 the fertilised egg is going to develop into a male, all the "masculine 

 seeds" will germinate; if the fertilised eg^ is going to develop into 

 a female all the "feminine seeds" will germinate. If the sex is im- 

 perfectly differentiated, as in casual hermaphrodites, then some 

 "seeds" of both sets — masculine and feminine — may germinate in 

 the peculiar soil. It is easy to read "gene" for "seed", "develop" for 

 "germinate", and "cytoplasm" for "soil". 



To the question why the fact that the fertihsed ovum is going to 

 develop into a male (or a female) should ipso facto imply that all 

 the masculine (or the feminine) characters are to find expression* 



