3OO Heredity. 



cross-breeding we might deduce a law which would give the 

 answer to the question proposed in the present chapter. It may 

 be thus stated : 



The mixture of two unequal races tends to efface the less per- 

 fect of the two. When a white man marries a negress, their child 

 is a mulatto. When two mulattoes of equal blood intermarry, their 

 child is whiter than themselves. This fact is an application of 

 a general law of nature, in accordance with which mixed forms 

 have a tendency to return to the types from which they are sprung, 

 and in the struggle for life the more perfect type prevails. 1 



Cases of unilateral crossing give some curious results. When 

 the white is united to the black, and then with the half-bred 

 progeny, the white type is seen to predominate more and more in 

 every generation. The pure type reappears in the fifth generation. 

 When this unilateral crossing takes place with the pure negro on 

 the one side, and successive generations of mulattoes on the other, 

 less time is required to bring back the perfect negro type. It 

 reappears in the third generation. 



In a large part of South America (Brazil, the Argentine Repub- 

 lic, Paraguay, etc.) a fact of great importance is found occurring 

 with considerable uniformity. From numerous and trustworthy 

 testimonies it appears that ' in that vast region, where these two 

 races are crossed in so large a scale, the European type always 

 prevails in the long run. . In Brazil, men of "mixed blood," of all 

 degrees of hybridization, are numerous, forming a new population, 

 which is ever growing more indigenous and coming nearer to the 

 white type, and, judging from what is taking place all over South 

 America, they will finally absorb all the other elements of the 

 population.' M. de Quatrefages is not clear whether this fact is 

 to be taken as a proof of the ascendancy of race. He is rather 

 inclined to suppose that it is due to conscious selection in cross- 

 breeding, the process being as a general rule unilateral, and in 

 favour of the white race. However this may be, 'it is a result of 

 great importance, for in this struggle between races, the victory 



1 Except where it is impeded by the action of its surroundings, as appears to 

 be the case in Peru, where the half-breed population has a strong tendency to 

 return to the indigenous type. 



