THEORY OF THE SYSTEM. 339 



doms of nature. To form the classes into Kingdoms, and 

 to comprehend these within the still higher idea of Nature, 

 is a problem belonging to Natural History in general, from 

 which the Natural History of every particular kingdom 

 must borrow these higher ideas. 



In order to give a general view of the subject, it will be 

 useful shortly to repeat the whole process of developing 

 these ideas, and the systematical unities themselves. 



All material bodies are distinguished, according to their 

 most general differences, into organic and inorganic natu- 

 ral productions (. 70- 



Organic nature comprehends two kingdoms, the Animal 

 and the Vegetable (. 8.) : inorganic nature comprehends 

 only one, the Mineral Kingdom (. 9.). 



The Mineral Kingdom is a series of natural-historical 

 genera, the succession of which is determined according to 

 their greater or less agreement or similarity (. 226.). It 

 contains three classes. 



Every class comprehends part of the series of genera col- 

 lected into several orders. The classes are not of the same 

 extent ; and the orders which they contain are joined by 

 an equal degree of similarity (. 228.). 



Every order is an assemblage of several genera in their 

 regular succession ; hence it is likewise a portion of the 

 general series of genera. The genera comprised within 

 an order, present equal degrees of similarity (. 227.). 



Every genus is an assemblage of similar species ; it is a 

 unity in the series of genera. The species within the ge- 

 nera are connected by equal degrees of similarity (. 225.). 



Every species is an assemblage of homogeneous indi- 

 viduals ; the individuals of a species are connected by the 

 series of characters, that is to say, by real natural-historical 

 transitions (. 221. 222.). 



The individual is the simple mineral, produced by na- 

 ture, either singly (. 160.), or in various compositions 

 (. 178... 189.). It is the only systematic idea which imme- 

 diately refers to nature, or to which an object of observation 



