EMBRYOLOGICAL VIEW OF THE PROBLEM 4S3 



and sperm-production, and this, we think, may be expressed 

 as a difference in " physiological gearing." 



Embryological Yiew of the Problem. — It does not seem 

 necessary or useful to suppose that there are in the germ-cells 

 any constituent particles or determinants corresponding to 

 maleness or femaleness. The germ-cell is physiologically deter- 

 mined to produce an egg-bearing or a sperm-bearing organism — 

 according to its degree of anabolic preponderance it will become a 

 producer of eggs or of sperms. The ratio of anabolism to kata- 

 bolism in the female (^) is assumed to be always greater than 

 the corresponding ratio in the male (^). It is not unlikely 

 that this physiological bias towards different metabolic ratios is 

 due rather to the cytoplasm of the nucleus than to the chromo- 

 somes, and it must be remembered that in its physiological 

 relations every cell is a co-operative organisation with continual 

 interactions between nucleoplasm and cytoplasm — a " cell- 

 firm " in short. 



But when we come to consider all the appanages of the primary 

 sexual characters of egg-producing and sperm-producing— 

 the differences in the gonads, in their ducts, in the external 

 genital organs, and in the secondary sexual characters — then it 

 becomes, as it seems to us, both necessary and useful to people 

 the chromosomes with definite representative particles or deter- 

 minants corresponding to these varied structures. 



We believe that these are ultimately traceable to germinal 

 variations or mutations, appearing now in the sperms and again 

 in the eggs, or it may be in the combination of the two. We 

 suppose that these have, like other -variations and mutations, 

 run the gauntlet of selection in one or more of its various modes, 

 and have sooner or later come to form part of the normal inherit- 

 ance, just Hke any other peculiarities unconnected with sex. 

 We suppose that they are represented in all gametes, whether 

 ova or spermatozoa, and that their expression or latency depends 

 on the physiological determination of the gamete towards 



