ANATOMICAL SYSTEMS. 321 



liarities. The most striking of its features is the prin- 

 ciple laid down that the type of development of animals 

 is one and the same from Man to the Monad, implying a 

 complete negation of the principle advocated by Cuvier, 

 that the four primary divisions of the animal kingdom 

 are characterized by different plans of structure. It is 

 very natural that Ehrenberg, after having illustrated so 

 fully and so beautifully as he did the natural history of 

 many organized beings, which, up to the publication of 

 his investigations, were generally considered as entirely 

 homogeneous ; after having shown how highly organized 

 and complicated the internal structure of many of them 

 is ; after having proved the fallacy of the prevailing 

 opinions respecting their origin, should have been led to 

 the conviction that there is, after all, no essential differ- 

 ence between these animals, which were then regarded as 

 the lowest, and those which were placed at the head of 

 the animal creation. The investigator who had just 

 revealed to the astonished scientific world the compli- 

 cated systems of organs which can be traced in the body 

 of microscopically small Rotifera must have been led 

 irresistibly to the conclusion that all animals are equally 

 perfect, and have assumed, as a natural consequence of 

 the evidence he had obtained, that they stand on the 

 same level with one another, as far as the complication 

 of their structure is concerned. Yet the diagram of his 

 own system shows that he himself could not resist the 

 internal evidence of their unequal structural endowment. 

 Like all other naturalists, he places Mankind at one end 

 of the animal kingdom, and such types as have always 

 been considered as low at the other end. 



Man constitutes, in his opinion, an independent cycle, 

 that of nations, in contra-distinction to the cycle of 



Y 



