mutatus._ See _De Claris Oratoribus_, s. 315 and 316.

[e] Cicero is here said to have been a complete master of philosophy,
which, according to Quintilian, was divided into three branches,
namely, physics, ethics, and logic. It has been mentioned in this
section, note [c], that Cicero called logic a contracted and close
mode of eloquence. That observation is fully explained by Quintilian.
Speaking of logic, the use, he says, of that contentious art, consists
in just definition, which presents to the mind the precise idea; and
in nice discrimination, which marks the essential difference of
things. It is this faculty that throws a sudden light on every
difficult question, removes all ambiguity, clears up what was
doubtful, divides, develops, and separates, and then collects the
argument to a point. But the orator must not be too fond of this close
combat. The minute attention, which logic requires, will exclude what
is of higher value; while it aims at precision, the vigour of the mind
is lost in subtlety. We often see men, who argue with wonderful craft;
but, when petty controversy will no longer serve their purpose, we see
the same men without warmth or energy, cold, languid, and unequal to
the conflict; like those little animals, which are brisk in narrow
places, and by their agility baffle their pursuers, but in the open
field are soon overpowered. _Hæc pars dialectica, sive illam dicere
malimus disputatricem, ut est utilis sæpe et finitionibus, et
comprehensionibus, et separandis quæ sunt differentia, et resolvendâ
ambiguitate, et distinguendo, dividendo, illiciendo, implicando; ita
si totum sibi vindicaverit in foro certamen, obstabit melioribus, et
sectas ad tenuitatem vires ipsâ subtilitate consumet. Itaque reperias
quosdam in disputando mirè callidos; cum ab illâ verò cavillatione
discesserint, non magis sufficere in aliquo graviori actu, quam parva
quædam animalia, quæ in angustiis mobilia, campo deprehenduntur._