THEORIES OF LAMARCK AND DARWIN 385 



inheritance of the same. His theory is comprehensive, 

 so much so that he includes mankind in his general con- 

 clusions. 



Lamarck supposed that an animal having become 

 adapted to its surroundings would remain relatively stable 

 as to its structure. To the objection raised by Cuvier that 

 animals from Egypt had not changed since the days when 

 they were preserved as mummies, he replied that the climate 

 of Egypt had remained constant for centuries, and therefore 

 no change in its fauna was to be expected. 



Species. — Since the question of the fixity of species is the 

 central one in theories of evolution, it will be worth while to 

 quote Lamarck's definition of species: "All those who have 

 had much to do with the study of natural history know that 

 naturalists at the present day are extremely embarrassed in 

 defining what they mean by the word species. . . . We call 

 species every collection of individuals which are alike or 

 almost so, and we remark that the regeneration of these 

 individuals conserves the species and propagates it in con- 

 tinuing successively to reproduce similar individuals." He 

 then goes on with a long discussion to show that large collec- 

 tions of animals exhibit a great variation in species, and that 

 they have no absolute stability, but "enjoy only a relative 

 stability." 



Herbert Spencer adopted and elaborated the theory of 

 Lamarck. He freed it from some of its chief crudities, such 

 as the idea of an innate tendency toward perfection. In 

 many controversies Mr. Spencer defended the idea of the 

 transmission of acquired characters. The ideas of Lamarck 

 have, therefore, been transmitted to us largely in the Spence- 

 rian mold and in the characteristic language of that great 

 philosopher. There has been but little tendency to go to 

 Lamarck's original writings. Packard, whose biography of 

 Lamarck appeared in 1901, has made a thorough analysis 



