The Evidence for Evolution 



in others. Colour, feathering, build, even the instincts and the 

 voice, vary enormously as between different varieties. In short, 

 there is hardly any obvious character that has not, in one or other 

 of the breeds, undergone great modification. As Darwm remarked, 

 any naturalist coming upon such a group of forms in nature 

 would have no hesitation in placing them in different species or 

 genera, or even perhaps in different families. Even granting 

 that the conditions of domestication are peculiar, we must admit 

 that if such large changes can occur in a few centuries, it is possible 

 that man has evolved from the lowest of living organisms during a 

 period some hundreds of thousands of times as long. 



But marked changes of type occur not only under conditions 

 of domestication ; nor is it necessary to infer the occurrence 

 of any such changes without actual direct evidence. The forma- 

 tion of new types occurs in nature, and has taken place under the 

 very eyes of scientific observers. Perhaps the most striking case 

 that can be quoted is that of Lamarck's Evening Primrose, which, 

 under the observation of Prof. De Vries in Amsterdam, produced 

 some half-dozen of ' sports ' which seem well entitled to rank as 

 new species. Fig. 5 shows the parent plant and two of the 

 new types that were produced by it. One is a dwarf in habit, 

 the other is characterised by the greatly increased breadth of its 

 foliage. Others showed different peculiarities. One might quote 

 many other instances of violent changes of type — of the appear- 

 ance of six-fingered children, whose peculiarity was afterwards 

 inherited ; of web-footed pigeons, and of new varieties of fruits, 

 flowers, and vegetables. The causes of such ' sports ' or mutations 

 are unknown, but their moderately frequent occurrence is abund- 

 antly demonstrated. Such facts show, at all events, that the 

 old conception of species as permanently fixed, unchanging types, 

 can no longer reasonably be held. 



Not al] of the abnormalities which thus suddenly appear, we 

 know not how or wherefore, are new. Many recall characters in 

 lower or older groups, and may reasonably be interpreted as 

 ' reversions.' Thus the horse's leg shown in Fig. 6 bears a well- 

 developed side toe, in place of the small vestige that is normally 



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