CLEAR FROST IN WINTER 151 



53. the plumy wave. Feathery wreaths of snow. 



71. azure gloss. Russell Lowell (My Study Windows : 

 A Good Word for Winter), speaking of snow surfaces, says 

 ' Not less rare are the tints of which they are capable the faint 

 blue of the hollows for the shadows in snow are always blue.' 

 Thomson anticipated the remark. 



NATURAL SELECTION 



IF, under changing conditions of life, organic beings 

 present individual differences in almost every part of 

 their structure, and this cannot be disputed ; 



If there be, owing to their geometrical rate of 

 increase, a severe struggle for life at some age, season, 

 or year, and this certainly cannot be disputed ; 



Then, considering the infinite complexity of the 

 relations of all organic beings to each other, and to 

 their conditions of life, causing an infinite diversity in 

 10 structure, constitution, and habits to be advantageous 

 to them, it would be a most extraordinary fact if no 

 variations had ever occurred useful to each being's own 

 welfare, in the same manner as so many variations 

 have occurred useful to man. 



But, if variations useful to any organic being ever 

 do occur, assuredly individuals thus characterized will 

 have the best chance of being preserved in the struggle 

 for life ; and, from the strong principle of inheri- 

 tance, these will tend to produce offspring similarly 

 20 characterized. 



This principle of preservation, or the survival of the 

 fittest, I have called Natural Selection. 



CHARLES DAKWIN : Origin of Species. 



