254 



LAMAECK'S THEOEY OF THE 



[Ch. XXXIV. 



had a common point of departure. What, then, was the 

 single stem from which so many varieties of form have 

 ramified ? Were there many of these, or are we to refer the 

 origin of the whole animate creation, as the Egyptian 

 priests did that of the universe, to a single egg ? 



In the absence of any positive data for framing a theory 

 on so obscure a subject, the following considerations were 

 deemed by Lamarck of importance to guide conjecture. 



In the first place, if we examine the whole series of known 

 animals, from one extremity to the other, when they are 

 arranged in the order of their natural relations, we find that 

 we may pass progressively, or, at least, with very few inter- 

 ruptions, from beings of more simple to those of a more com- 

 pound structure ; and, in proportion as the complexity of 

 their organisation increases, the number and dignity of their 

 faculties increase also. Among plants, a similar approxima- 

 tion to a graduated scale of being is apparent. Secondly, it 

 appears, from geological observations, that plants and animals 

 of more simple organisation existed on the globe before the 

 appearance of those of more compound structure, and the 

 latter were successively formed at more modern periods ; each 

 new race being more fully developed than the most perfect of 

 the preceding era. 



Of the truth of the last-mentioned geological theory, 

 Lamarck seems to have been fully persuaded ; and he also 

 shows that he was deeply impressed with a belief prevalent 

 amongst the older naturalists, that the primeval ocean in- 

 vested the whole planet long after it became the habitation 

 , of living beings; and thus he was inclined to assert the 

 priority of the types of marine animals to those of the 

 terrestrial, so as to fancy, for example, that the testacea of 

 the ocean existed first, until some of them, by gradual evolu- 

 tion, were improved into those inhabiting- the land. 



These speculative views had already been, in a great degree, 

 anticipated by Demaillet in his Telliamed, and by several other 

 writers who preceded Lamarck ; so that the tables were com- 

 pletely turned on the philosophers of antiquity, with whom 

 it was a received maxim, that created things were always 

 most perfect when they came first from the hands of their 



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