102 The American Naturalist. [February, 



-correspondingly complex and exact formulation. The advent 

 of the doctrine of evolution into the organic sciences involves 

 the necessity of making such readjustments of our method of 

 formulation as may be called for. It is with reference to this 

 condition and the present action of naturalists regarding it, 

 that I address you to-day. The subject may be considered 

 under the three heads of Taxonomy, Phylogeny, and Nomen- 

 clature. 



I. Taxonomy. 



Taxonomy or classification is an orderly record of the struc- 

 tural characters of organic beings. The order observed is an 

 order of values of these characters. Thus we have what we call 

 specific or species value, generic value, family value, and so on. 

 These values are not imaginary or artificial, as some would 

 have us believe, but they are found in nature. Their recogni- 

 tion by the naturalist is a matter of experience, and the ex- 

 pression of them is a question of tact. Their recognition rests 

 on a knowledge of morphology, or the knowledge of true iden- 

 tities and differences of the parts of which organic beings are 

 composed. The formulation of these values in classification 

 foreshadows the evolutionary explanation of their origin, and 

 is always the first step necessary to the discovery of a phylo- 

 geny. 



Taxonomy, then, is, and always has been, an arranging of 

 organic beings in the order of their evolution. This accounts 

 for the independence of the values of taxonomic characters, of 

 any other test. Thus, no character can be alleged to be of 

 high value because it has a physiological value, or because it 

 has no physiological value. A physiological character may 

 or may not have a taxonomic value. The practiced taxo- 

 nomist finds a different test of values, which is this. He first 

 endeavors to discover the series of organic forms which he 

 studies. He learns the difference between its beginning and 

 its ending. His natural divisions are the steps or stages which 

 separate the one extremity from the other. The series may 

 be greater or they may be lesser, i. e., more or less comprehen- 

 sive, and it is to the series of different grades that we give the 

 different names of the genus, family, order, etc. 



