PROGRESS OF THE RACE 287 



tendency to degenerate can be combated and changed 

 into an upward bias ? In order to discover such a 

 means it is needful to gather all possible information 

 with regard to the primary factors of organic evolution 

 in the human race that is to say, variation and 

 heredity. Galton was the first to show that the laws 

 of variation and heredity in man are closely similar 

 to the same laws in other organisms. He showed, too, 

 that mental and moral characters are inherited just 

 as strongly as physical characters a fact which is 

 by no means so generally appreciated as it should 

 be, in spite of the further evidence adduced by Prof. 

 Karl Pearson. 



Many people believe that the progress of the race 

 can be directly and permanently affected by improve- 

 ments in education and the amelioration of social 

 conditions. It is certain that the qualities of any 

 person health, character, efficiency, and so forth, 

 depend upon his environment and upbringing, as well 

 as upon his hereditary endowments. It is therefore 

 necessary, before we proceed farther, to arrive at some 

 estimate of the relative importance of inherent qualities 

 and of education of nature and nurture respectively. 

 Practically the only piece of good evidence upon this 

 point is one which we owe to the researches of Galton. 



Galton's data are derived from the history of twins. 

 Now, human twins are of two kinds. One of these 

 kinds corresponds to the young of those animals which 

 normally bear two or more at a birth, each being 

 derived from a separate ovum, whilst the second kind 

 is the result of the development of two embryos from 



