1899] THE SCOPE OF NATURAL SELECTION 197 



principle for selection to rely upon, since the male and female lines of 

 heredity would be largely in harmony over the earlier stages of 

 development, the tendency to vary being increased towards the later 

 stages, thus the requisite stability and variability would be largely 

 obtained. Finally, this theory involves no very great assumption ; it 

 is, when examined, very little more than a series of inferences drawn 

 from peculiarities of life that appear to be nearly or completely uni- 

 versal in application, being dependent solely on the assumptions of 

 mechanical and chemical limits to growth, the latter being no longer 

 an assumption, but an established fact in some instances, on the 

 innate capacity for growth, qualitative and quantitative specialisa- 

 tion, and upon the conclusion that protoplasm is never directly in- 

 fluenced by climatic conditions. The theory of co-incident variability 

 and the non-inheritance of acquired responses would equally accord 

 with this theory as with Weismann's, while it would account for those 

 cases of modifications which have been effected during the early stages 

 of development. 



In conclusion, I have endeavoured to show reason for believing 

 that the principle of selection, when rightly viewed, is the only theory 

 which is capable of explaining the various phenomena in their entirety; 

 that the properties existing in the lowest forms of life do afford 

 sufficient material for natural selection to act upon, and therefore, until 

 it can be shown that another theory is in more complete accordance 

 with the facts, that natural selection must be regarded as the dominant 

 factor of evolution. 



The Ghotto, 

 Hamfton-on-Tiiajies. 



