CHARLES DARWIN 317 



that he found good reasons for ranking Homo sapiens simply 

 in the animal kingdom, was a particularly effective prepara- 

 tion for ideas which came later. Are we not to-day also still 

 far behind Linnaeus, when we are unwilling to recognise 

 the existence of human strains with their distinctive char- 

 acteristics, and the necessity for selective breeding, although 

 this is recognised in the case of all domestic animals ? 



A second great creator of order appeared a hundred years 

 later, Charles Darwin namely; but he was also much more 

 than a mere systematist. His great and original survey of 

 all living things no longer starts from existing life as we 

 know it at the present time, but rests upon the beginning of 

 an understanding of the gradual development of life upon 

 earth, a development upwards from the simplest to ever 

 higher forms of living organisms. The view generally held 

 and regarded as valid, which Darwin found when he began 

 his work, in spite of Linnaeus' ideas having already reached 

 further, regarded the different species of living creatures 

 as having been set upon the earth from the beginning in 

 their existing forms, and having then reproduced them- 

 selves from one generation to another in an identical form. 

 However, petrified remains of animals had been found in 

 excavations in the earth's crust, the forms of which were 

 different from those of present-day animals, and it had to be 

 concluded that these were of various ages, in accordance 

 with the arrangement of the layers of rock one above the 

 other. It thus appeared that in course of time certain forms 

 died out, while new ones appeared, as though one had 

 gradually taken the place of the other. 



This gave a proof of the appearance of different species at 

 successive times in the history of the earth, and hence almost 

 of a gradual development of these species.^ This fact 



1 Lamarck had already concluded from this fact, and for other reasons, 

 in his Philosophic zoologique (Paris, 1809), that the assumption of the 

 invariability of plant and animal species is untenable, and gave decided 

 expression to this view. 



