BRANCHES OF THE ANIMAL KINGDOM. 209 



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 reference 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 Invertebrata simply because they 

 have no skeleton, but because of that something which 

 even Professor Owen fails to express, 1 and which yet 

 exists, the one cavity of the body in the Invertebrata con- 

 taining all organs, whilst theVertebrata have one distinct 

 cavity for the centres of the nervous system, and another 

 for the organs of the vegetative life. This acknowledg- 

 ment is due to Lamarck as truly as it would be due to 

 Aristotle not to accuse him of having denied the Inverte- 

 brata any fluid answering the office of the blood, though 

 he calls them Anaima; for he knew nearly as well as 

 we now know, that a nutritive fluid moves 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 presence, in the former, 

 of those masses, forming the main bulk of the body, 

 which consist of flesh and bones, as well as of blood and 

 nerves, and constitute another of the leading features dis- 

 tinguishing Vertebrata and Invertebrata. Ehrenberg pre- 

 sents the same relations between the same beings as 

 expressed by their nervous system. If we now take the 

 expressions of Aristotle, Lamarck, Oken and Ehrenberg 



1 Comparafc. Anat. of Inv., 2d edit., p. 11. 



P 



