PRINCIPLES OF CLASSIFICATION 133 



objects (or varieties in this case) into groups 

 according to some one character arbitrarily 

 selected, while the natural method attempts 

 to take into consideration all the characters 

 of the varieties in question. 



This matter may be made plain by an ex- 

 ample. In nurserymen's catalogs apples are 

 usually classified according to one character 

 namely, season of ripening; that is, they are, 

 given a purely arbitrary classification. There 

 may be two varieties almost exactly alike as 

 regards growth of tree, color, texture, and 

 flavor of fruit, and all other qualities ; yet if 

 one happens to ripen in August and the other 

 in December, the two will go to the opposite 

 ends of the nurseryman's list. 



We would have similarly an arbitrary clas- 

 sification if we selected any other one charac- 

 ter for our basis of assortment. We might 

 decide to classify according to form, which is 

 one of the best of all arbitrary ways of classi- 

 fying apples. We would put the round 

 apples into one group, the oblate apples into 

 another, the oblong varieties into a third, and 

 the conic varieties into a fourth. Still we 

 would be sure to find placed together certain 

 apples which, though of the same form, were 



