CHAPTER VI 



BI-PARENTAL REPRODUCTION 



El-parental reproduction said to be a cause of progressive variations A 

 complete error Evidence from the common experiences of life 

 The scientific evidence Equidse Pigs Goats Rabbits Sheep 

 Pigeons Fowls Ducks Plants Reversion seldom observable 

 under conditions of Natural Selection Often observable under 

 conditions of artificial selection Reversion the cause of the deterior- 

 ation of useless parts The function of bi-parental reproduction 

 in evolution. 



111. WE are now in a position to consider the part played 

 in nature by sexual or bi-parental reproduction. Though 

 nearly all biologists have supposed that progressive variation, 

 and therefore evolution, is largely due to bi-parental repro- 

 duction, there is, in fact, in the whole range of biological litera- 

 ture not one iota of evidence which supports that view. Men, 

 as in so many instances, have accepted a dogma without 

 proof, and have held it without inquiry. There is no veil like 

 the veil of familiarity. The misleading analogy, so frequently 

 made, that two dissimilar germ-plasms are like an acid and a 

 base, the union of which results in a product which is dis- 

 similar from both, has often warped their judgments. The 

 common experiences of life and the massive and precise 

 testimony accumulated by science have been ignored under 

 the influence of what is plainly an obsession. 



112. Take a few of the common experiences of life. Suppose 

 a man and a woman vary from their parents and from the 

 specific type, the one by being unusually tall and dark, and 

 the other by being unusually short and fair; and sup- 

 pose they have offspring. Of what type should we expect 

 the offspring to be ? Should we expect some unusual pro- 

 gressive variation to result from this union of comparatively 

 dissimilar germ-plasms ? Assuredly not. Our common experi- 

 ence is that, though exceptionally the child of such a couple 

 may be as tall and dark as the father or as short and fair as 



67 



