MODERNS lOLOGY 585 



The problem of heredity was dealt with from an entirely dilTerent 

 point of view by Francis Galton (i82.i-i9ii). He was a cousin of Darwin's 

 and his life reminds one of the latter's. The son of wealthy parents, he 

 studied medicine, but never graduated, for as soon as he had inherited his 

 father's fortune, he went on voyages, first to Eygpt and then to south-west 

 Africa, where he made valuable geographical discoveries. After his return 

 to England he applied himself for some years to meteorology, but eventually 

 devoted his life entirely to heredity research. He began by seeking to prove 

 experimentally Darwin's pangenesis theory, which, it will be remembered, 

 assumes that particles from all the organs of the body are transmitted 

 through the sexual products from generation to generation and bring about 

 the offspring's resemblance to the parents. Galton injected blood from a 

 foreign rabbit into a pair of grey ones, in the hope that their progeny would 

 thereby become dappled, which would have been a proof of the pangenesis 

 theory; but his expectations were not fulfilled, the young of the grey rabbits 

 turning out grey. In virtue of this experience Galton produced a heredity 

 theory of his own: all the organic units existing in a fertilized egg he terms 

 "stirp," and he believes that the majority of these are used for purposes of 

 organic structure, but that a number of them are left over, and these give 

 rise to the sexual cells, the qualities of which are thus not influenced by 

 the conditions of life of the individual. He gave expression to this opposi- 

 tion to the doctrine of the heredity of acquired characters as early as in 

 1875 — ^^^^ ^^' before Weismann — but after that he passed on to quite 

 different developmental problems. From the very beginning the evolution 

 of man had been a subject of special interest to him; he is extremely fond 

 of demonstrating physiological phenomena with the aid of social and politi- 

 cal comparisons. The fact that brothers and sisters are often so unlike one 

 another is explained by a reference to an electoral body, where a very slight 

 difference of opinion can often give rise to an entirely different result when 

 it comes to the vote; in the same way, a slight change in the hereditary sub- 

 stance can produce a complete change in the appearance of the individual. 



Galton s statistical method 

 In a later work. Natural Inheritance, Galton has presented the statistical 

 heredity-theory that has made his name famous; his stirp theory is here 

 abandoned and the transmission of acquired characters is no longer denied 

 so absolutely as it had been before. Instead, basing his arguments on an 

 exhaustive research-material, he tries to find out the variational direction 

 in a large number of human qualities. The most highly valued of his investi- 

 gations have been those into the question of height; the height of a number 

 of parents was compared with that of their grown-up children arranged in 

 series from the shortest to the tallest; there is thus obtained an average 

 height, which is possessed by the majority, while the less numerous 



