D. APPLETON & CO. S PUBLICATIONS. 



BY 



Means of Natural Selection ; 



OR. 



THE PRESERVATION OF FAVORED RACES 



ix TUB 



STRUGGLE FOR LIFE. 



BY 



One Volume. 12mo. Cloth. $2.00. 



&quot; His first point is to show that species are in many cases not well 

 defined, and that the whole order of natural history seems to be in a 

 state of mutation, by reason of constant variations. Thus even under 

 domestication, important changes may be introduced by intercrossing, 

 by selection of the oest individuals for propagation, by crossing parent* 

 marked by however slight, but favorable peculiarities. 



&quot;His second point is what he terms the universal and necessary 

 itruggle for existence. This follows from the high geometrical ratio 

 of increase common to all beings. If there were no catastrophes, 

 any one of the existing species would be sufficiently numerous in a 

 few thousand years to cover the whole earth, to the exclusion of every 

 thing else. 



&quot; His third point is to prove that this struggle is directed by the 

 law of natural selection. Even the races of domestic animals may be 

 constantly improved and modified by choosing the best individuals 

 for propagation. Nature brings the same discipline to bear upon the 

 whole domain of animal and vegetable life. She seizes at once upon 

 any slight variation that is favorable, and perpetuates it ; in the uni 

 versal pressure, any variation that ia injurious is immediately xtiu- 

 guished.&quot; 



