Criticisms of Theory of Natitral Selection. 345 



opposite objection has sometimes been urged viz. 

 that we ought never to find inferior forms of or- 

 ganization in company with superior, because in the 

 struggle for existence the latter ought to have exter- 

 minated the former. Or, to quote the most recent 

 expression of this view, "in every locality there 

 would only be one species, and that the most highly 

 organized ; and thus a few superior races would par- 

 tition the earth amongst them to the entire exclusion 

 of the innumerable varieties, species, genera, and orders 

 which now inhabit it V Of course to this statement 

 it would be sufficient to enquire, On what would these 

 few supremely organized species subsist? Unless 

 manna fell from heaven for their especial benefit, it 

 would appear that such forms could under no circum- 

 stances be the most improved forms ; in exterminating 

 others on such a scale as this, they would themselves 

 be quickly, and very literally, improved off the face 

 of the earth. But even when the statement is not 

 made in so extravagant a form as this, it must neces- 

 sarily be futile as an objection unless it has first been 

 shown that we know exactly all the conditions of the 

 complex struggle for existence between the higher 

 and lower forms in question. And this it is impos- 

 sible that we ever can know. The mere fact that 

 one form has been changed in virtue of this struggle 

 must in many cases of itself determine a change in 

 the conditions of the struggle. Again, the other 

 and closely allied forms (and these furnish the best 

 grounds for the objection) may also have under- 

 gone defensive changes, although these may be 

 less conspicuous to our observation, or perhaps less 

 1 Syme, on the Modification of Organisms, p. 46. 



