I30 LAMARCK, HIS LIFE AND WORK 



the first genealogical tree ; his phylogeny, in the 

 second volume of his Philosophie zoologique (p. 463), 

 proves that he realized that the forms leading up to 

 the existing ones were practically extinct, as we now 

 use the word. Lamarck in theory was throughout, 

 as Houssay well says, at one with us who are now 

 living, but a century behind us in knowledge of the 

 facts needed to support his theory. 

 V^ In this first published expression of his views on 

 palseontology, we find the following truths enumerated 

 on which the science is based : (i) The great length of 

 geological time ; (2) The continuous existence of ani- 

 mal life all through the different geological periods 

 without sudden total extinctions and as sudden re- 

 creations of new assemblages ; (3) The physical envi- 

 ronment remaining practically the same throughout in 

 general, but with (4) continual gradual but not catas- 

 trophic changes in the relative distribution of land 

 and sea and other modifications in the physical geog- 

 raphy, changes which (5) caused corresponding changes 

 in the habitat, and (6) consequently in the habits of 

 the living beings ; so that there has been all through 

 geological history a slow modification of life-forms. // 

 ■»^ Thus Lamarck's idea of creation is evolutional rdX\\ev 

 than uniformitarian. There was, from his point of 

 view, not simply a uniform march along a dead level, 

 but a progression, a change from the lower or gener- 

 alized to the higher or specialized — an evolution or 

 unfolding of organic life. In his effort to disprove 

 catastrophism he failed to clearly see that species, as 

 we style them, became extinct, though really the 

 changes in the species practically amounted to extinc- 



