THE FALLACIES OF NATURAL SELECTION. 145 



enemies or competitors for the same place or food; 

 and if these enemies or competitors be in the least 

 degree favored by any slight change of climate, they 

 will increase in numbers, and as each area is already 

 stocked with inhabitants, the other species will decrease. 

 When we travel southwards and see a species decreas- 

 ing in numbers, we may feel sure that the cause lies 

 quite as much in other species being favored, as in this 

 one being hurt. So it is, when we travel northward, 

 but in a somewhat lesser degree, for the number of 

 species of all kinds, and therefore of competitors, de- 

 creases northward; hence, in going northward, or in 

 ascending a mountain, we far oftener meet with stunted 

 forms, due to the directly injurious action of climate, 

 than we do in proceeding southward, or descending a 

 mountain. When we reach the Arctic regions, or snow- 

 capped summits, or absolute deserts, the struggle for 

 life is almost exclusively with the elements." 



Again he says : 



"Battle within battle must ever be recurring, with 

 varying success; and yet, in the long run, the forces 

 are so nicely balanced, that the face of Nature remains 

 uniform, for long periods of time, though assuredly 

 the merest trifle would often give the victory to one 

 organic being over another. Nevertheless, so pro- 

 found is our ignorance, and so high our presumption, 

 that we marvel when we hear of the extinction of an 

 organic being; and, as we do not see the cause, we in- 

 voke cataclysms to desolate the world, or invent laws 

 on the duration of the forms of life." 



Speaking of a forest, in order to exemplify the 



Struggle for Existence, he says : 



"What a struggle between the several kinds of 

 trees, must here have gone on during long centuries, 

 each annually scattering its seeds, by the thousand; 

 13* 



