80 MEANING OF OHDERS. 



the idea that the system of man, the most perfect 

 created being, is the measure for the whole Ani- 

 mal Kingdom, and that in analyzing his organi- 

 zation we have the clew to all organized beings. 

 The structure of man includes two systems of 

 organs : those which maintain the body in its in- 

 tegrity, and which he shares in some sort with 

 the lower animals, the organs of digestion, cir- 

 culation, respiration, and reproduction ; and that 

 higher system of organs, the brain, spinal mar- 

 row, and nerves, with the organs of sense, on 

 which all the manifestations of the intelligent 

 faculties depend, and by which his relations to 

 the external world are established and controlled : 

 the whole being supported by a solid bony frame 

 and surrounded by flesh, muscles, and skin. On 

 account of this fleshy envelope of the hard parts 

 in all the higher animals, Oken divided the Ani- 

 mal Kingdom into two groups, the Vertebrates 

 and Invertebrates, or, as he called them, the 

 " Eingeweide und Fleisch-Thiere" which we 

 may translate as the Intestinal Animals, or those 

 that represent the intestinal systems of organs, 

 and the Flesh Animals, or those that combine all 

 the systems of organs under one envelope of 

 flesh. Let us examine a little more closely this 

 singular theory, by which each branch of the In- 

 vertebrates becomes, as it were, the exponent of 

 a special system of organs, while the Vertebrates, 



