248 FROM THE GREEKS TO DARWIN 



many directions, the extremities of which are 

 truly isolated points." This early conception of 

 the principle of divergence in Lamarck's mind 

 may be comj)ared to a fir-tree with a single cen- 

 tral stem and radiating branches. He says, in 

 effect:' 



Such a natural series has recently been denied, 

 and some have substituted for a gradated series a 

 reticulated series, in which animals and plants are 

 spread out as upon a map. Such a reticulated series 

 has seemed sublime to some modern writers, and Her- 

 mann has attempted to add probability to it. But 

 those who study more profoundly the organization of 

 living bodies, and occupy themselves less exclusively 

 with the consideration of species, will see that this 

 view will have to be entirely abandoned. 



Lamarck's later (1809) conception of the tree 

 of life, not as radiating from a single central 

 stem, but as branching from the roots into larger 

 and smaller stems, so far as we know was the 

 first of the great phyletic trees, the construction 

 of which has since occupied so large a portion of 

 the energy of zoologists and has been carried to 

 the farthest extreme by Haeckel. 



In his second table Lamarck derives the fishes 

 from the molluscs ; but in a third table, published 

 in 1815, while it is of the same branching charac- 

 ter, he declares that he can no longer connect the 



'^Loc. cit., pp. 40, 41. 



