Perhaps, however, the relationship alone does not constitute a case. Perhaps there is a necessity of either the addition of a preposition (as in _of a father_), or of a change in form (as in _father's_). In this case (although _child_ be not so) _father's_, _of a father_, and _to a father_, are all equally cases. Now it has long been remarked, that if the use of a preposition constitute a case, there must be as many cases in a language as there are prepositions, and that "_above a man_, _beneath a man_, _beyond a man_, _round about a man_, _within a man_, _without a man_, shall be cases as well as _of a man_, _to a man_, and _with a man_." § 209. For etymological purposes, therefore, it is necessary to limit the meaning of the word case; and, as a sort of definition, it may be laid down that _where there is no change of form there is no case_. With this remark, the English language may be compared with the Latin. _Latin._ _English._ _Sing. Nom._ _Pater_ _a father._ _Gen._ _Patris_ _a father's._ _Dat._ _Patri_ _to a father._ _Acc._ _Patrem_ _a father._ _Abl._ _Patre_ _from a father._ Here, since in the Latin language there are five changes of form, whilst in English there are but _two_, there are (as far, at least, as the word _pater_ and _father_ are concerned) three more cases in Latin than in English. It does not, however, follow that because in the particular word _father_ we have but two cases, there may not be other words wherein there are more than two. § 210. Neither does it follow, that because two words may have the _same form_ they are necessarily in the _same case_; a remark which leads to the distinction between _a real and an accidental identity of form_. In the language of the Anglo-Saxons the genitive cases of the words _smið_, _ende_, and _dæg_, were respectively, _smiðes_, _endes_, and _dæges_; whilst the nominative plurals were, _smiðas_, _endas_, and _dægas_. But when a change took place, by which the vowel of the last syllable in each word was ejected, the result was, that the forms of the genitive singular and the nominative plural, originally different, became one and the same; so that the identity of the two cases is an accident. This fact relieves the English grammarian from a difficulty. The nominative plural and the genitive singular are, in the present language of England, identical; the apostrophe in _father's_ being a mere matter of orthography. However, there was _once_ a difference. This modifies the previous statement, which may now stand thus:--_for a change of case there must be a change of form existing or presumed_. § 211. _The number of our cases and the extent of language over which they spread._--In the English language there is undoubtedly a _nominative_ case. This occurs in substantives, adjectives, and pronouns (_father_, _good_, _he_) equally. It is found in both numbers.