26 THE GRAMMAR OF SCIENCE 



home to the reader the possibility of this better than by 

 citing some of the conclusions to which the theory of 

 heredity elaborated by the German biologist Weismann 

 introduces us, Weismann's theory lies on the borderland 

 of scientific knowledge ; his results are still open to dis- 

 cussion, his conclusions to modification.^ But to indicate 

 the manner in which science can directly influence conduct, 

 we will assume for the time being Weismann's main con- 

 clusion to be correct. One of the chief features of his 

 theory is the non-inheritance by the offspring of character- 

 istics acquired by the parents in the course of life. Thus 

 good or bad habits acquired by the father or mother in 

 their lifetime are not inherited by their children. The 

 effects of special training or of education on the parents 

 have no direct influence on the child before birth. The 

 parents are merely trustees who hand down their com- 

 mingled stocks to their offspring. From a bad stock can 

 come only bad offspring, and if a member of such a stock 

 is, owing to special training and education, an exception 

 to his family, his offspring will still be born with the old 

 taint," Now this conclusion of Weismann's — if it be 

 valid, and all we can say at present is that the arguments 

 in favour of it are remarkably strong — radically affects 

 our judgment on the moral conduct of the individual, and 

 on the duties of the state and society towards their 

 degenerate members. No degenerate and feeble stock 

 will ever be converted into healthy and sound stock by 

 the accumulated effects of education, good laws, and 



1 His theory of the "continuity of the germ plasm" is in many respects 

 open to question, but his conclusion as to acquired characteristics being 

 uninherited stands on firmer ground. See Weismann, Essays o?t Heredity 

 and Kindred Biological Problems, Oxford, 1889. A good criticism will be 

 found in C. LI. Morgan's Animal Life and Intelligence, chap. v. ; a sum- 

 mary in W. P. Ball's Are the Effects of Use and Disuse Inhei-ited? Tlie 

 reader should also consult P. Geddes and J. A. Thomson, The Evolution of 

 Sex, and a long discussion in Nature, vols. xl. and xli, {sub indice, Weismann, 

 Heredity). 



2 Class, poverty, localisation do much to approximately isolate stock, to 

 aggregate the unfit even in modern civilisation. The mingling of good and 

 bad stock due to dispersion is not to be commended, for it degenerates the 

 good as much as it improves the bad. What we need is a check to the 

 fertility of the inferior stocks, and this can only arise with new social habits 

 and new conceptions of the social and the anti-social in conduct. 



