HISTORY OF ZOOLOGY. 11 



outset informed the reader to what position of relationship the new 

 species was to be assigned. 



In his characterization of the various systematic groups Linnaeus 

 broke completely with the hitherto-prevailing custom. His 

 predecessors (as Gessner, Aldrovandus) in their Natural Histories 

 had given a verbose and detailed description of each animal, from 

 which the beginner was scarcely able to see what was specially 

 characteristic for that animal, a matter which should have been 

 emphasized in the definition. Linnaeus, 011 the other hand, intro- 

 duced brief diagnoses, which in a few words, never in sentence 

 form, gave only what was necessary for recognition. Thus a way 

 was found which insured comprehensibility in the enormously 

 increasing number of known animals. 



Influence of the Linnean System. But in the great superiority 

 of the Linnean System lay at the same time the germ of the one- 

 sided development which zoology came to take under his influence. 

 The logical perfecting of the system, which undoubtedly had 

 become necessary, gave that a brilliant aspect, and hid the fact 

 that classification is not the ultimate purpose of investigation, but 

 only an important and indispensable aid to it. In the zeal for 

 naming and classifying animals, the higher goal of investigation, 

 knowledge of the nature of animals, was lost sight of, and the 

 interest in anatomy, physiology, and embryology flagged. 



From these reproaches we can scarcely spare Linnaeus himself, 

 the father of this tendency. For while in his " Systema Naturae " 

 he treated of a much larger number of animals than any earlier 

 zoologist, he brought about no deepening of our knowledge. The 

 manner in which he divided the animal kingdom, in comparison 

 with the Aristotelian system, is rather a retrogression than an 

 advance. Linnaeus divided the animal kingdom into six classes: 

 Mammalia, Aves, Amphibia, Pisces, Insecta, Yermes. The first 

 four classes correspond to Aristotle's four groups of animals with 

 blood. In the division of the invertebrated animals into Insecta 

 and Vermes Linnaeus stands undoubtedly behind Aristotle, who 

 attempted, and in part successfully, to set up a larger number of 

 groups. 



But in his successors, even more than in Linnaeus himself, we 

 see the damage wrought by the systematic method. The diagnoses 

 of Linnaeus were for the most part models, which, mutatis 

 mutandis, could be employed for new species with little trouble. 

 There was needed only some exchanging of adjectives to express 

 the differences. With the hundreds of thousands of different 



