376 OUTLINES OF EVOLUTIONAKY BIOLOGY 



successively to everything that we see, as to everything which 

 exists and which is unknown to us? 



" Assuredly, whatever may have been His will, the immensity 

 of His power is always the same ; and in whatever manner this 

 supreme will may have been executed, nothing can diminish 

 its grandeur." 1 



Lamarck seems to have been the first to insist upon the 

 branching character of evolutionary series ; after speaking 

 of such series he goes on : 



" I do not wish to say thereby that existing animals form a 

 very simple series, everywhere equally graduated ; but I say 

 that they form a branching series, irregularly graduated, and 

 which has no discontinuity in its parts, or which, at least, has 

 not always had, if it be true that, in consequence of some species 

 having been lost, such discontinuity occurs anywhere. It 

 results from this that the species which terminate each branch 

 of the general series are connected, at least on one side, with 

 other neighbouring species which shade into them." 2 



Like Buffon, he lays great stress upon the action of the 

 environment in modifying organisms : 



" Many facts teach us that in proportion as the individuals of 

 one of our species change their situation, their climate, their 

 manner of living or their habits, they thereby receive influences 

 which little by little change the consistency and the proportions 

 of their parts, their form, their faculties, even their organization ; 

 so that everything in them participates, in the course of time, in 

 the transformations which they experience. 



" In the same climate, very different situations and exposures 

 at first cause the individuals exposed thereto simply to vary ; 

 but, in the course of time, the continual difference in situation of 

 the individuals of which I am speaking, which live and reproduce 

 themselves successively in the same circumstances, causes in 

 them differences which become, in some way, essential to their 

 existence ; so that, after many generations have succeeded one 

 another, these individuals, which belonged originally to another 

 species, find themselves in the end transformed into a new species, 

 distinct from the other. 



" For example, if the seeds of a grass, or of any other plant 

 natural to a damp meadow, be transported by any chance, first 

 to the slope of a neighbouring hill, where the soil, although more 

 elevated, is still sufficiently cool to permit of the plant main- 

 taining itself, and if afterwards, after having lived there and 



1 Op. cit.. Tom. I, pp. 56, 57. 



2 Ibid., p. 59. 





