208 ESSAY ON CLASSIFICATION. 



philosopher can be surprised to find that zoologists have 

 instinctively adopted natural groups, in the animal and 

 vegetable kingdoms, even before the question of the 

 character and of the very existence of such groups in 

 nature was raised. Did not nations speak, understand, 

 and write Greek, Latin, German and Sanscrit, before it 

 was even suspected that these languages and so many 

 others were akin \ Did not painters produce wonders 

 with colours, before the nature of light was understood \ 

 Had not men been thinking about themselves and the 

 world, before logic and metaphysics were taught in 

 schools 1 Why, then, should not observers of nature have 

 appreciated rightly the relationship between animals or 

 plants before getting a scientific clue to the classifications 

 which, they were led to adopt as practical ? 



Such considerations, above all others, have guided and 

 encouraged me when seeking for the meaning of all 

 these systems, so different one from the other in their 

 details, and yet so similar in some of their general fea- 

 tures. The history of our science shows how early some 

 of the principles, which obtain to this day, have been 

 acknowledged by all reflecting naturalists. Aristotle, for 

 instance, already knew the principal differences which 

 distinguish Vertebrata from all other animals; and his 

 distinction of Enaima and Anaima 1 corresponds exactly 

 to that of Vertebrata and Invertebrata of Lamarck, 2 and 

 to that of Flesh- and Gut-Animals of Oken, 3 and to that of 

 Myeloneura and Ganglioneura of Ehrenberg; 4 and one 

 who is at all familiar with the progress of science at diffe- 

 rent periods can but smile at the claims to novelty or 



1 Histor. Anim., Lib. I, ch. 5 and 6. 3 Naturphilosophie, 3d edit., p. 400. 



2 Anim. Vert., 2d edit., vol. i, p. 4 Das Naturreich des Measchen; 

 313. a diagram upon a large sheet, folio. 



