116 HEREDITY AND SELECTION IN SOCIOLOGY 



species would be practically nU, owing to the uncertainty in the 

 vital conditions. 



It is evident that in one of their results consanguinity and self- 

 fertihsation must be analogous ; both modes of reproduction will 

 result in making the germ-plasm monotonous. As we have 

 already said, sexual reproduction has fewer risks for the 

 species than consanguinity, and the same holds good of self- 

 fertilisation. 



In parthenogenesis the second maturation division does not 

 occur ; consequently, the number of heterogeneous ids will not be 

 reduced, and may remain constant during long periods ; although 

 fresh elements are not introduced, those heterogeneous elements 

 already possessed when the sexual method of reproduction was 

 abandoned by the species will not be ousted by an increasing 

 invasion of homogeneous elements. If a parthenogenetic species 

 is eUminated, this will be due, not to the spread of constitutional 

 defects, but because the individuals are not sufficiently plastic to 

 readapt themselves, or because, in the case of species which have 

 been adapted for a long time, a readaptation is too slow in 

 coming. 



Turning now to the results of consanguineous unions in the 

 species which interests us most in our present study, we come to 

 the results of consanguinity in human society. Eeliable statistics 

 are difficult to obtain, but it may be said that, as a general rule, 

 no judgment can be pronounced for or against consanguinity as 

 such. Everything depends upon the condition of the individuals 

 who practise it. Historically, exogamy, " as at first estabUshed> 

 imphes an extremely abject condition of women, a brutal treat- 

 ment of them, and an entire absence of the higher sentiments that 

 accompany the relations of the sexes. Associated with the lowest 

 type of political Ufe, it is also associated with the lowest type of 

 domestic life." And, on the other hand, " endogamy, which at 

 the outset must have characterised the more peaceful groups, 

 and which has prevailed as societies have become less hostile, is 



