140 ESSAY ON CLASSIFICATION 



ers produce wonders with colors before the nature of light was un- 

 derstood? Had not men been thinking about themselves and the 

 world before logic and metaphysics were taught in schools? Why 

 then should not observers of nature have appreciated rightly the re- 

 lationship between animals or plants before getting a scientific clue 

 to the classifications they were led to adopt as practical? 



Such considerations, above all others, have guided and encouraged 

 me while I was seeking for the meaning of all these systems, so dif- 

 ferent one from the other in their details, and yet so similar in some 

 of their general features. The history of our science shows how early 

 some of the principles, which obtain to this day, have been acknowl- 

 edged 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 corresponds 

 exactly to that of Vertebrata and Invertehrata of Lamarck, or to that 

 of Flesh- and Gut-Animals of Oken, or to that of Myeloneura and 

 Ganglioneura of Ehrenberg; and one who is at all familiar with the 

 progress of science at different periods can but smile at the claims 

 to novelty or originality so frequently brought forward for views 

 long before current among men. Here, for instance, is one and the 

 same fact presented in different aspects; first by Aristotle with refer- 

 ence to the character of the formative fluid, next by Lamarck with 

 reference to the general frame — for I will do Lamarck the justice 

 to believe that he did not unite the Invertehrata simply because they 

 have no skeleton but because of that something, which even Professor 

 Owen fails to express and which yet exists, the one cavity of the body 

 in Invertehrata containing all organs, whilst Vertebrata have one 

 distinct cavity for the centres of the nervous system and another for 

 the organs of the vegetative life. This acknowledgment is due to 

 Lamarck as truly as it would be due to Aristotle not to accuse him 

 of having denied the Invertehrata any fluid answering the office of 

 the blood, though he calls them Anaima; for he knew nearly as well 

 as we now know that there moves a nutritive fluid in their body, 

 though that information is generally denied him because he had no 

 correct knowledge of the circulation of the blood. 



Again, when Oken speaks of Flesh-Animals he does not mean that 

 Vertebrates consist of nothing but flesh or that the Invertebrates have 

 no muscular fibres; but he brings prominently before us the pres- 



