OF THE FITTEST. 



AMONG organic beings in a state of nature there is some 

 individual variability. This is an admission about 

 which there can be no dispute. But the mere existence of 

 individual variability and of a few well-marked varieties, 

 though necessary as the foundation for the work, assists us 

 but little in understanding how species originate in nature. 

 Those exquisite adaptations of one part of the organization to 

 another part, and to the conditions of life, and of one organic 

 being to another being, which we know to exist, seem as 

 mysteries. We see them in the humblest parasite that clings 

 to the hairs of a quadruped or the feathers of a bird, in the 

 structure of the beetle that dives through the water, and in 

 the plumed seed that is wafted by the gentlest breeze. In 

 short, we see beautiful adaptations everywhere and in every 

 part of the organic world. And yet, how few have paused 

 while admiring these beautiful and wonderful co-adaptations 

 to ask themselves the question : How have these been 

 perfected ? 



If the existence of any well-marked varieties be admitted, 

 how is it that these varieties, which may be denominated 

 incipient species, become ultimately converted into good 

 and distinct species, which in the generality of cases obviously 

 differ from each in a greater degree than do the varieties of 

 the same species ? How do these groups of species, which 

 constitute what are authoritatively called genera, and which 

 differ from each other more than do the species of the same 

 genus, arise ? All these results, as will presently be seen, fol- 

 low from the Struggle for Existence. Owing to this struggle, 



