RACES OF MEN. 205 



upon the sexual propensities, as with the Digger Indians, the 

 Fuegians, the Andamanese, the Wauraus of the Guianas, the Bush- 

 men, and the tribes along the Gabbon river, there we find reproduc- 

 tion taking place at the earliest possible age, and the lowest grade of 

 intelligence. Where we find some special circumstances or customs 

 that delay the age at which reproduction takes place, as with the 

 Patagonians, the North, American Indians, and the Polynesians, 

 there we find a considerably higher grade of intelligence. Where 

 we find the custom of marrying late in life, as was customary with 

 the Greeks and the Romans, there we find a very high grade of in- 

 telligence. And where we find a fortuitous succession of very late 

 births, there we find the very great men of the world's history. 

 In other words, the longer the time in which the individuals have 

 in which to use, develop and strengthen their brains before repro- 

 duction begins, the greater and more powerful are the brains of 

 their descendants. By referring to page 51 it will be seen that this 

 is but a slightly different statement of the laws as formulated by 

 Lamarck nearly a hundred years ago. 



