THE LATEST STAGE 249 



its line of descent. Increase of this knowledge is 

 coming fast, and should soon form a valuable guide 

 to the physician, to the sociologist, perhaps to the 

 statesman. 



From the more philosophic aspect, the results of 

 Mendel and his rediseoverers complete on one side the 

 Darwinian period, and on another show its insufficiency, 

 and open a new chapter. In the original theory of 

 the origin of species by natural selection, still held as 

 against the Mendelians by many biologists, it is the 

 small variations of organisms round the mean form 

 that supply the material for selection to work upon. 

 It is not easy to see how enough isolation of more 

 successful beings can occur to establish inbreeding, 

 and so build up a new species. But the large differ- 

 ences found by Mendelians, and the complete separa- 

 tion of unit characters, do much to diminish this 

 difficulty. In their view, new varieties may arise 

 almost per saltum, and establish themselves at once. 



On the other hand, these new and unexpected 

 phenomena showed that Darwin, as he himself well 

 knew, had not said the last word on evolution, and 

 gave a welcome check to some of the more confident 

 speculations of the newer prophets of Darwinism. 



Another aspect of evolutionary philosophy also has 

 been affected by recent research. Though Lamarck's 

 theory gave up its pride of chief place to that of 

 Darwin, many accredited evolutionists continued to 

 preach and act as though characters in man acquired 

 by the reaction of the environment as by exercise, 

 training, or education were handed down in their 

 developed form to his offspring. Thus a comforting 

 doctrine arose that we need but improve the acquire- 



