4 A STUDY IN HEREDITY 



world is round. It is no longer considered by them 

 as an interesting guess, a mere hypothesis, a thing 

 that may be doubted. It is regarded as a proven 

 and accepted fact. But scientific belief filters down- 

 wards very slowly. Nearly four hundred years have 

 elapsed since the Copernican doctrine of the spherical 

 shape of the world and of its revolution round the 

 sun was first enunciated, and to this day there are 

 doubters even among the most civilised peoples. 

 The theory of evolution was brought prominently 

 before the world scarce forty years ago ; its progress 

 has been much more rapid than the Copernican 

 theory, for, as I say, it is already accepted by 

 almost the whole of the educated world ; but, as is 

 natural, the masses still reject it. At least they 

 reject it nominally. Really I suppose no sane 

 human being in existence doubts it. All that objec- 

 tors usually do is to set limits to its operations, which 

 vary with the extent of their knowledge. Thus, 

 while many men decline the doctrine that all species 

 of plants and animals had a common origin, all men, 

 even the most savage, believe that the different 

 races of mankind sprang in the far distant past from 

 a common stock — Heathen Gods, Adam and Eve, 

 a species of lower animals ; it matters not which. 

 But to-day the different races differ vastly. Some 

 are white, others black, yellow, or copper-coloured. 

 Some are big, others are small. Some have long 



