BIOLOGY OF MAN 1167 



fact that most of these organic advances take place with extreme 

 slowness. It looks as if we must look elsewhere for the secret of 

 recent progress. 



In this connection the sociological idea is that man progresses 

 by registering his advances outside himself. The social heritage 

 (the environment of culture) is in its own way as important as what 

 Galton called the "natural inheritance", whose vehicle is the germ- 

 plasm. What is only adumbrated in ant-hill, termitary, beehive, 

 beaver-village and the like, becomes in mankind of paramount 

 influence. Man registers his progress outside himself in institutions, 

 maimers and customs, morals and laws, also in languages and 

 literatures, in arts and crafts, in traditions and rituals, in permanent 

 products also, and how much more. Is it not the improvement of 

 this social heritage that accounts for the raising of the human mental 

 average among civilised peoples, supposing this rise to be a fact ? 



That this is the whole truth is improbable, especially if it be 

 admitted that the organic transmissibility of individually acquired 

 modifications is more than doubtful. Before Weismann's scepticism 

 infected most biologists it was usual to think and speak as if a son 

 must be hereditarily the better for the careful education which his 

 parents received; witness the old aristocratic saying that "it takes 

 three generations to make a gentleman". It was believed that 

 modificational improvements acquired by parents as the direct 

 result of ameliorative peculiarities in nurture could be in some 

 representative way entailed on their offspring. But there are few 

 well-established facts to show that this is the main way in which 

 organic evolution works. In face of this scepticism we do not depre- 

 ciate the value of the progressive factors in the social heritage. 

 Indeed, they should be ranked as more important than ever, if we 

 are forced to the conclusion that their ameliorative influences have 

 to play afresh on each generation. 



But if mankind be progressing, in parts at least, and if this be 

 not due either to the transmission of acquired characters, or to a 

 slow variational uplift in mental ability, what, then, is happening? 

 The open secret, we think, is this: that there has been an increase 

 in social susceptibility or impressionability. Mankind seldom, if ever, 

 breeds deliberately for mental ability; nor does he sift towards that 

 quality with consistency or with enthusiasm. The same may be said 

 in regard to health. But what man does more largely breed for and 

 select for is susceptibility to the influences of the social heritage. 

 As these influences become richer and more powerful there is an 

 automatic increase in the nicety of the selective process. Apart 

 from the physically rotten and the ethically rebellious, there is no 

 type so likely to be a failure as that which is unsusceptible to the 

 ameliorative influences of the social heritage. No doubt the social 

 heritage is of mixed quality; but the integrative has on the whole 



