5 o6 HEREDITY AND SEX 



for we find ourselves unable to get away from the conviction 

 that there is no sex-determinant or factor at all, in the morpho- 

 logical or in the Mendelian sense, but that what settles the sex 

 is a metabolism-rhythm, or a relation of nucleoplasm and cyto- 

 plasm, or a relation between Anabolism and Katabolism. 



All through the series of organisms — and of animals in par- 

 ticular — from the active Infusorians and the passive Sporozoa 

 to feverish birds and sluggish reptiles, we read alternatives or 

 antitheses between liberal expenditure of energy and a more 

 conservative habit of storing. This primarily depends on the 

 ratio between disruptive (katabolic) processes and constructive 

 (anabolic) processes, and we regard the sexes as expressions of 

 the same contrast within a given species. 



According to this view, the deep constitutional difference 

 between the male and the female organism, which makes of the 

 one a sperm-producer and of the other an egg-producer, is due 

 to an initial difference in the balance of chemical changes. 

 " The female seems to be relatively the more constructive, 

 whence her greater capacity for sacrifices in maternity ; the male 

 relatively the more disruptive, whence his usually more vivid 

 life, his explosive energies in action." In short, the sexes 

 express a fundamental difference in the rhythm of metabolism. 



As we have seen, many sets of facts lead to the conclusion 

 that each sex-cell has a complete equipment of masculine and 

 feminine characters, and it may be that the liberating stimulus 

 which calls the one set or the other into expression or develop- 

 ment, is afforded by the metabolism conditions that have been 

 set up in the field of operations, which lead also to the establish- 

 ment of ovary or spermary, as the case may be. As Dr. C. E. 

 Walker says in his interesting work Hereditary Characters (1910) : 

 " The evidence then seems to suggest that the secondary sexual 

 characters are dependent for their development upon the presence 

 of the sexual glands in the individual, and that the potentiality 

 of producing them is present in all individuals of both sexes." 



