12 DARWINISM STATED BY DARWIN HIMSELF. 



searches, and those of Dr. Mitchell, that the evidence as 

 to any evil thus caused is conflicting, but on the whole 

 points to its being very small. From the facts given in 

 this volume we may infer that with mankind the mar- 

 riages of nearly related persons, some of whose parents 

 and ancestors had lived under very different conditions, 

 would be much less injurious than that of persons who 

 had always lived in the same place and followed the same 

 habits of life. Nor can I see reason to doubt that the 

 widely different habits of life of men and women in 

 civilized nations, especially among the upper classes, 

 would tend to counterbalance any evil from marriages 

 between healthy and somewhat closely related persons. 



DEVELOPMENT OF THE TWO SEXES IN PLANTS. 



Under a theoretical point of view it is some 

 * gain to science to know that numberless struct- 

 ures in hermaphrodite plants, and probably in hermaph- 

 rodite animals, are special adaptations for securing an 

 occasional cross between two individuals ; and that the 

 advantages from such a cross depend altogether on the 

 beings which are united, or their progenitors, having 

 had their sexual elements somewhat differentiated, so 

 that the embyro is benefited in the same manner as is a 

 mature plant or animal by a slight change in its condi- 

 tions of life, although in a much higher degree. 



Another and more important result may be deduced 

 from my observations. Eggs and seeds are highly ser- 

 viceable as a means of dissemination, but we now know 

 that fertile eggs can be produced without the aid of the 

 male. There are also many other methods by which 

 organisms can be propagated asexually. Why then have 

 the two sexes been developed, and why do males exist 



