if inferior they are biologically a detriment.
But if the new arrivals are different, if they represent a different subspecies of Homo sapiens, the question is more serious, for it involves the problem of crossing races which are biologically more or less distinct. Genetics can throw some light on this problem.
Waiving for the moment all question as to the relative quality of two distinct races, what results are to be expected from crossing? It (1) gives an increase of vigor which diminishes in later generations and (2) produces recombination of characters.
The first result may be disregarded, for the various races of man are probably already much mixed, and too closely related, to give rise to much hybrid vigor in crosses.
The second result will be favorable or unfavorable, depending on the characters which go into the cross; and it is not possible to predict the result in human matings, because the various racial characters are so ill known. It is, therefore, not worth while here to discuss at length genetic theory. In general it may be said that some valuable characters are likely to disappear, as the result of such crosses, and less desirable ones to take their place. The great bulk of the population resulting from such racial crosses is likely to be more or less mongrel in nature. Finally, some individuals will appear who combine the good characters of the two races, without the bad ones.
The net result will therefore probably be some distinct gain, but a greater loss. There is danger that complex and valuable traits of a race will be broken down in the process of hybridization, and that it will take a long time to bring them together again. The old view that racial crosses lead fatally to race degeneration is no longer