l6o FROM LAMARCK TO ST. HILAIRE. 



Biologie, The two latter sections were never com- 

 pleted. It is important to note that in this work hei 

 projects a scale of life somewhat similar to that oi 

 Bonnet and of Aristotle. This shows that in his 

 mind at that time, the history of life presented itself 

 as a vertical chain of masses of organisms not of 

 species ; so far as appears, he had not then developed 

 the branching idea. This chain he puts forth to 

 show the ' deo'radation' or Qrradation from the hi^h- 

 est to the lowest forms, indicating the march of 

 Nature in its progressive developments. Here and 

 elsewhere Lamarck acknowledges his indebtedness 

 to the Greeks, especially to Aristotle. Two main 

 principles are brought out in this work anticipating 

 his later theory of the causes of Evolution : first, it 

 is not organs which have given rise to habits, but 

 habits, modes of life, and environment which have 

 given rise to organs ; as illustrated by the blindness 

 of the mole, by the presence of teeth in mammals, 

 and the absence of teeth in birds. His second 

 principle is, that life is an order and condition of 

 things in the parts of all bodies w^hich possess it, 

 which renders possible all the organic movements 

 within. 



There is no evidence in this work that Lamarck 

 had seen Darwin's Zoonomia. The parallelism 

 with the Zoo7iomia comes out much more promi- 

 nently in Lamarck's most important speculative 

 work, the Philosophie Zoologique, published in 

 1809, i^ which his earlier views are developed and 



