380 THE STUDY OF ANIMAL LIFE CHAP. 



That each parent contributes almost equally to the 

 offspring suggests the two-sided responsibility of parent- 

 age. As regards Mendelian characters the offspring will 

 show Avith more or less completeness the dominant char- 

 acters of its parents ; as regards blending characters the 

 inheritance is probably in the first instance dual, but 

 beyond that multiple, for ancestral contributions may 

 go to build up the final mosaic result." 



If we adopt Weismann's conclusion that individually 

 acquired modifications are not transmitted, we are saved 

 from the pessimism suggested by the abnormal functions 

 and environments of our civilisation. 



And just in proportion as we doubt the transmission 

 of desirable acquired characters, so much the more 

 should we desire to secure that improved conditions of 

 life foster the individual development of each successive 

 generation. 



That pathological conditions, innate in the organism, 

 tend to be transmitted, suggests that men should be in- 

 formed and educated as to the undesirability of parentage 

 on the part of abnormal members of the community. 



The widest problems of heredity are raised when we 

 substitute " fraternities ' for individuals, or make the 

 transition to social inheritance the relation between 

 the successive generations of a society. 



Thus Sir Francis Galton called attention to the regularity 

 observed in the peculiarities of great populations through- 

 out a series of generations. " The large do not always 

 beget the large, nor the small the small ; but yet the 

 observed proportion between the large and the small, 

 in each degree of size and in every quality, hardly varies 

 from one generation to another." A specific average is 

 sustained. This is not because each individual leaves 

 his like behind him, for this is not the case. It is rather 

 due to the fact of a regular regression or deviation which 

 brings the offspring of extraordinary parents in a definite 

 ratio nearer the average of the stock. 



" However paradoxical it may appear at first sight, it 

 is theoretically a necessary fact, and one that is clearly 

 confirmed by observation, that the stature of the adult 



