The second class of words consists of those, which in their simplest state suggest but one idea, as the word man; but which by two changes of termination in our language suggest one secondary idea of number, as the word men; or another secondary idea of the genitive case, as man's mind, or the mind of man. These words by other changes of termination in the Greek and Latin languages suggest many other secondary ideas, as of gender, as well as of number, and of all the other cases described in their grammars; which in English are expressed by prepositions. This class of words includes the NOUNS SUBSTANTIVE, or names of things, of common grammars, and may be conveniently divided into three kinds. 1. Those which suggest the ideas of things believed to possess hardness and figure, as a house or a horse. 2. Those which suggest the ideas of things, which are not supposed to possess hardness and figure, except metaphorically, as virtue, wisdom; which have therefore been termed abstracted ideas. 3. Those which have been called by metaphysical writers reflex ideas, and mean those of the operations of the mind, as sensation, volition, association. Another convenient division of these nouns substantive or names of things may be first into general terms, or the names of classes of ideas, as man, quadruped, bird, fish, animal. 2. Into the names of complex ideas, as this house, that dog. 3. Into the names of simple ideas, as whiteness, sweetness. A third convenient division of the names of things may be into the names of intire things, whether of real or imaginary being; these are the nouns substantive of grammars. 2. Into the names of the qualities or properties of the former; these are the nouns adjective of grammars. 3. The names of more abstracted ideas as the conjunctions and prepositions of grammarians. These nouns substantive, or names of intire things, suggest but one idea in their simplest form, as in the nominative case singular of grammars. As the word a stag is the name of a single complex idea; but the word stags by a change of termination adds to this a secondary idea of number; and the word stag's, with a comma before the final s, suggests, in English, another secondary idea of something appertaining to the stag, as a stag's horn; which is, however, in our language, as frequently expressed by the preposition _of_, as the horn of a stag.