8 ESSAY ON CLASSIFICATION 



every period in the history of our globe in past geological ages,^ the 

 general relations, the numeric proportions, and the relative impor- 

 tance of all the types of the animal kingdom have been ever chang- 

 ing, until their present relations were established. Here then the 

 individuals of one species, as observed while living, simultaneously 

 exhibit characters which, to be expressed satisfactorily and in con- 

 formity to what nature tells us, would require the establishment, not 

 only of a distinct species, but also of a distinct genus, a distinct fam- 

 ity, a distinct class, a distinct branch. Is not this in itself evidence 

 enough that genera, families, orders, classes, and types have the same 

 foundation in nature as species, and that the individuals living at 

 the time have alone a material existence, they being the bearers, not 

 only of all these different categories of structure upon which the 

 natural system of animals is founded, but also of all the relations 

 which animals sustain to the surrounding world — thus showing 

 that species do not exist in nature in a different way from the higher 

 groups, as is so generally believed? 



The divisions of animals according to branch, class, order, family, 

 genus, and species, by which we express the results of our investiga- 

 tions into the relations of the animal kingdom, and which constitute 

 the primary question respecting any system of Zoology seem to me 

 to deserve the consideration of all thoughtful minds. Are these divi- 

 sions artificial or natural? Are they the devices of the human mind to 

 classify and arrange our knowledge in such a manner as to bring it 

 more readily within our grasp and facilitate further investigations, 

 or have they been instituted by the Divine Intelligence as the cate- 

 gories of his mode of thinking? "^ Have we perhaps thus far been only 



' A series of classifications of animals and plants, exhibiting each a natural system 

 of the types known to have existed simultaneously during the several successive geo- 

 logical periods, considered singly and without reference to the types of other ages, 

 would show in a strong light the different relations in which the classes, the orders, 

 the families, and even the genera and species, have stood to one another during each 

 epoch. Such classifications would illustrate, in the most impressive manner, the im- 

 portance of an accurate knowledge of the relative standing of all animals and plants, 

 which can only be inferred from the perusal even of those palaeontological works in 

 which fossil remains are illustrated according to their association in different geolog- 

 ical formations; for in all these works the remains of past ages are uniformly referred 

 to a system established upon the study of the animals now living, thus lessening the 

 impression of their peculiar combination for the periods under consideration. 



^ It must not be overlooked here that a system may be natural, that is, may agree in 

 every respect with the facts in nature, and yet not be considered by its author as the 

 manifestation of the thoughts of a Creator, but merely as the expression of a fact ex- 



