s. 485. _Syntactic convertibility._--The combination _to err_, is at this moment an infinitive verb. Nevertheless it can be used as the equivalent to the substantive _error_. _To err is human_=_error is human_. Now this is an instance of syntactic conversion. Of the two meanings, there is no doubt as to which is the primary one; which primary meaning is part and parcel of the language at this moment. The infinitive, when used as a substantive, can be used in a singular form only. _To err_=_error_; but we have no such form as _to errs_=_errors_. Nor is it wanted. The infinitive, in a substantival sense, always conveys a general statement, so that even when singular, it has a plural power; just as _man is mortal_=_men are mortal_. s. 486. _The adjective used as a substantive._--Of these, we have examples in expressions like the _blacks of Africa_--_the bitters and sweets of life_--_all fours were put to the ground_. These are true instances of conversion, and are proved to be so by the fact of their taking a plural form. _Let the blind lead the blind_ is not an instance of conversion. The word _blind_ in both instances remains an adjective, and is shown to remain so by its being uninflected. s. 487. _Uninflected parts of speech, used as substantive._--When King Richard III. says, _none of your ifs_, he uses the word _if_ as a substantive=_expressions of doubt_. {401} So in the expression _one long now_, the word _now_=_present time_. s. 488. The convertibility of words in English is very great; and it is so because the structure of the language favours it. As few words have any peculiar signs expressive of their being particular parts of speech, interchange is easy, and conversion follows the logical association of ideas unimpeded. _The convertibility of words is in the inverse ratio to the amount of their inflection._ * * * * * {402} CHAPTER II. SYNTAX OF SUBSTANTIVES. s. 489. The phenomena of convertibility have been already explained. The remaining points connected with the syntax of substantives, are chiefly points of either ellipsis, or apposition. _Ellipsis of substantives._--The historical view of phrases, like _Rundell and Bridge's_, _St. Pauls'_, &c., shows that this ellipsis is common to the English and the other Gothic languages. Furthermore, it shows that it is met with in languages not of the Gothic stock; and, finally, that the class of words to which it applies, is, there or thereabouts, the same generally. A. 1. The words most commonly understood, are _house_ and _family_, or words reducible to them. In Latin, _Dianae_=_aedem Dianae_.--Deutsche Grammatik, iv. 262. 2. _Country, retinue._--Deutsche Grammatik, iv. 262. 3. _Son_, _daughter_, _wife_, _widow_.--Deutsche Grammatik, iv. 262.--[Greek: Neleus Kodrou], Greek. B. The following phrases are referable to a different class of relations--