THE DETERMINATION OF SEX. 



45 



and conservative forms. Theories of " inherent " maleness or female- 

 ness were rejected, since practically merely verbal; more accurately, 

 however, they have been interpreted and replaced by a more material 

 conception, which finds the bias of the whole life, the resultant of its 

 total activities, to be a predominance of the protoplasmic processess 

 either on the side of disruption or construction. This conclusion has 

 still to receive cumulative proof; but one large piece of evidence is 

 now forthcoming, — that, namely, of the present chapter. If influ- 

 ences favoring katabolism make for the production of males, and if 

 anabolic conditions favor females, t?hen we are strengthened in our 

 previous conclusion — that the male is the outcome of predominant 

 katabolism, and the female of equally emphatic anabolism. 



YI. Weismann's Theory of Heredity. — In thinking of the 

 environment as a factor determining the sex, it is impossible to ignore 

 that such facts as we have noted above have some bearing upon the 

 problem of heredity. Much of the recent progress in the elucidation 

 of the facts of inheritance has been due to Weismann, who, in his 

 theory of the continuity of the germ-plasma, has restated the very 

 important and fundamental conception of a continuity between the 

 reproductive elements of one generation and those of the next. To 

 this restatement we shall afterwards have to refer: it is with another 

 position, not peculiar to but emphasized by the same authority, that 

 we have here to do, namely, with his denial of the inheritance of indi- 

 vidually acquired characters. Any new character exhibited by an 

 organism may arise in one of two ways, which it is easy enough to 

 distinguish theoretically: it may be an outcrop of some property 

 inherent in the fertilized egg-ceil, — that is, it may have a constitu- 

 tional or germinal origin; but, on the other hand, it may be impressed 

 upon the individual organism by the environment, or acquired in the 

 course of its functioning, — that is, it may have a functional or environ- 

 mental origin. Thus an increase of calcareous matter in an animal 

 might well be wholly of constitutional origin ; but a change to a new- 

 diet, or to a new medium, might be followed by modifications arising, 

 in one sense, from without. But all such functional and environmental 

 variations are, according to Weismann, restricted to the individual 

 organism; they are not transmissible. 



And why not? This denial of the inheritance of dints from with- 

 out, and of acquired habits other than constitutional, can be no 

 mere optimism on Weismann's part. It is, he maintains, a scientific 

 skepticism, based on the one hand on the absence of data demonstrat- 

 ing what we may still call the current belief; and on the other hand on 

 the improbability of changes produced as above explained reacting 

 from the "body" on the reproductive cells. If such a reaction do 



