NOTE II.--_On the shortening of final o in Latin poetry._
The fact that in Latin the accent was generally thrown back caused a strong tendency to shorten long final vowels. The one that resisted this tendency best was _o_, but this gradually became shortened as poetry advanced, and is one of the very few instances of a departure from the standard of quantity as determined by Ennius. There is one instance even in him: _Horrida Romuleum certamina pango duellum_. The words _ego_ and _modo_, which from their frequent use are often shortened in the comedians, are generally long in Ennius; Lucretius uses them as common, but retains _homo_, which after him does not appear. Catullus has one short _o_, _Virro_ (89, 1), but this is a proper name. Virgil has _sci0_ (_Aen._ iii. 602), but _ego, homo_, when in the arsis, are always elided, _e.g. Pulsus ego? aut; Graius homo, infectos. Spondeo_ which used to be read (_Aen._ ix, 294), is now changed to _sponde_. _Pollio_ is elided by Virgil, shortened by Horace (O. II. i. 14). He also has _mentio_ and _dixero_ in the _Satires_ (I. iv. 93, 104). A line by Maecenas, quoted in Suetonius, has _diligo_. Ovid has _cito, puto_ (_Am._ iii. vii. 2), but only in such short words; in nouns, _Naso_ often, _origo, virgo_, once each. Tibullus and Propertius are stricter in this respect, though Propertius has _findo_ (iii. or iv. 8 or 9, 35); Manilius has _leo, Virgo_ (i. 266), Lucan _Virgo_ (ii. 329), _pulmo_ (iii. 644), and a few others. Gratius first gives the imperative _reponito_ (_Cyn._ 56); Calpurnius, in the the time of Nero, the false quantities _quando ambo_, the latter (ix. 17) perhaps in a spurious eclogue; so _expecto_. In Statius no new licenses appear. Juvenal, however, gives _vigilando_ (iii. 232), an improper quantity repeated by Seneca (_Tro._ 264) _vincendo_, Nemesianus (viii. 53) _mulcendo_, (ix. 80), _laudano_. Juvenal gives also _sumito, octo, ergo_. The dat. and abl. sing. are the only terminations that were not affected. We see the gradual deterioration of quantity, and are not surprised that even before the time of Claudian a strict knowledge of it was confined to the most learned poets.
NOTE III.--_On parallelism in Virgil's poetry._