TAXONOMY. 315 



CHAPTER IX. 



TAXONOMY. 



SECTION I. THE PRINCIPLES OF CLASSIFICATION IN NATURAL 

 HISTORY. 



618. TAXONOMY, from two Greek words which signify arrange- 

 ment and law, is the study of classification. This is of utmost 

 importance in Natural History, on account of the vast number 

 of kinds to be set in order, and of relations (of agreement and 

 difference) to be noted. Botanical classification, when complete 

 and correct, will be an epitome of our knowledge of plants. 

 Arrangement according to kinds, and of special kinds under 

 the more general, is common to all subjects of study. But the 

 classification in Biological Natural History, that is in Botany and 

 Zoology, has a foundation of its own. 



619. The peculiarity of plants and animals is that they exist 

 as individuals, propagating their like from generation to genera- 

 tion in a series. Of such series of individuals there are very 

 many kinds, and the kinds have extremely various and unequal 

 degrees of resemblance. There are various gradations, but not 

 all gradations of resemblance. Between some, the difference is 

 so wide that it can be said only that they belong to the same 

 kingdom ; between others, the resemblance is so close that it 

 may be questioned whether or not they came from common 

 parents or near ancestors. 



620. The recognition of the perennial succession of similar 

 individuals gives the idea of SPECIES. The recognition of un- 

 equal degrees of likeness among the species is the foundation 

 of GENERA, ORDERS, CLASSES, and other groups of species. 



621. Individuals are the units of the series which constitute 

 species. The idea of individuality which we recognize through- 

 out the animal and vegetable kingdoms is derived from ourselves, 

 conscious individuals, and from our corporeal structure and 

 that of the higher brute animals. This structure is a whole, 

 from which no part can be abstracted without mutilation. Each 

 individual is an independent organism, of which the component 

 parts are reciprocally means and ends. Individuality is a main 



