Class, Classification. The former of these words denotes any group of several individuals, whatever be the principle on which they are ranged together, and is what is now so often absurdly called a category. A class may be either a species or genus, according as it contains or is contained by another class or classes. In the technical language, however, of Natural History, convenience dictates separate names for the several ranks of subaltern, genera, and species, such as order, genus, species, &c.; and class there stands for a very high and extensive genus, such as the class mammalia in zoology, and the class cryptogamia in botany.
Classification is the arranging individuals in classes or groups, and this may be done quite arbitrarily, or by selecting characteristics at pleasure, or by looking for such as are permanent and essentially connected with the objects which we place together because of them.
The last-named method is alone scientific, and the great classificatory sciences which we name collectively Natural History, not only demand methods strictly logical, such as good division and definition, but insight into essential characteristics, and the subordination of one set of such to another. It is in this latter respect that the botanical system introduced by Jussieu is so superior to that of Linnæus, the one being as it is called the natural, the other the artificial method.
