PERIOD OF LINNJEUS. 303 



possible, in our day, to realize how great was the influ- 

 ence of that work upon the progress of Zoology. 1 And 

 yet it acted like magic upon the age, and stimulated it to 

 exertions far surpassing any thing that had been done in 

 preceding centuries. Such a result must be ascribed 

 partly to the circumstance that he was the first man who 

 ever conceived distinctly the idea of expressing in a defi- 

 nite form what he considered to be a system of nature, 

 and partly also to the great comprehensiveness, simpli- 

 city, and clearness of his method. Discarding in his sys- 

 tem everything that could not easily be ascertained, he 

 for the first time divided the animal kingdom into dis- 

 tinct classes, characterized by definite features; he also 

 for the first time introduced orders into the system of 

 Zoology besides genera and species, which had been 

 vaguely distinguished before. 2 And, though he did not 

 even attempt to define the characteristics of these different 

 kinds of groups, it is plain, from his numerous writings, 

 that he considered them all as subdivisions of a succes- 

 sively more limited value, embracing a larger or smaller 

 number of animals, agreeing in more or less comprehen- 

 sive attributes. He expresses his views of these relations 

 between classes, orders, genera, species, and varieties, by 

 comparisons, in the following manner: 



1 To appreciate correctly the sue- eighth, and ninth, are reprints of the 

 cessive improvements of the classifi- sixth ; the eleventh is a reprint of 

 cation of Linnseus, we need only the tenth ; and the thirteenth, pub- 

 compare the first edition of the Sys- lishecl after his death, by Gmelin, is 

 tenia Naturae, published in 1735; a mere compilation, deserving of little 

 with the second, published in 1740; confidence. 



the sixth, published in 1748; the 3 See above, Sect. II, p. 301. The 



tenth, published in 1758 ; and the ytv-n neyirrra of Aristotle correspond, 



twelfth, published in 1 766, as they however, to the classes of Linnaaus ; 



are the only editions he revised him-- the *y4vn fj.tyd\a to his orders, 

 self. The third is only a reprint of 3 See Systeina Naturte, 12th edit., 



the first, the fourth and fifth are re- p. 13. 

 prints of the second ; the seventh, 



