THE HISTORY OF OUR SPECIES. 77 



analogous ideas of Kant, Owen, Treviranus, and other 

 philosophers of the commencement of the century 

 (which are quoted in the above work), did not amount 

 to more than certain general conclusions. They had 

 not that great lever which the " natural history of 

 creation" needed for its firm foundation on a criticism 

 of the dogma of fixed species ; this lever was first 

 supplied by Lamarck. 



The first thorough attempt at a scientific establish- 

 ment of transformism was made at the beginning of 

 the nineteenth century by the great French scientist, 

 Jean Lamarck, the chief opponent of his colleague, 

 Cuvier, at Paris. He had already, in 1802, in his Obser- 

 vations on Living Organisms, expressed the new ideas 

 as to the mutability and formation of species, which 

 he thoroughly established in 1809 in the two volumes 

 of his profound work, Pkilosophie Zoologique. In this 

 work he first gave expression to the correct idea, in 

 opposition to the prevalent dogma of fixed species, 

 that the organic " species " is an artificial abstraction, 

 a concept of only relative value, like the wider-ranging 

 concepts of genus, family, order, and class. He went 

 on to affirm that all species are changeable, and have 

 arisen from older species in the course of very long 

 periods of time. The common parent forms from 

 which they have descended were originally very 

 simple and lowly organisms. The first and oldest 

 of them arose by abiogenesis. While the type is 

 preserved by heredity in the succession of generations, 

 adaptation, on the other hand, effects a constant modifica- 

 tion of the species by change of habits and the exercise 

 of the various organs. Even our human organism has 

 arisen in the same natural manner, by gradual trans- 

 formation, from a group of pithecoid mammals. For 



