[II.18] prevent: anticipate.
[II.19] quarrel: cause of complaint.
[II.20] colour: pretext, plausible appearance.
[II.21] ll. 29-34 The general meaning of this somewhat obscure passage is, Since we have no show or pretext of a cause, no assignable ground or apparent ground of complaint, against Cæsar, in what he is, or in anything he has yet done, let us assume that the further addition of a crown will quite upset his nature, and metamorphose him into a serpent. The strain of casuistry used in this speech is very remarkable. Coleridge found it perplexing. On the supposition that Shakespeare meant Brutus for a wise and good man, the speech seems unintelligible. But Shakespeare must have regarded him simply as a well-meaning but conceited and shallow idealist; and such men are always cheating and puffing themselves with the thinnest of sophisms, feeding on air and conceiving themselves inspired, or "mistaking the giddiness of the head for the illumination of the Spirit."
[II.22] ll. 35, 59, 70 Re-enter | Enter Ff.
[II.23] first Ff | Ides Theobald.
[II.24] The Folio reading 'first of March' cannot be right chronologically, though it is undoubtedly what Shakespeare wrote, for in Plutarch, Marcus Brutus, he read: "Cassius asked him if he were determined to be in the Senate-house the first day of the month of March, because he heard say that Cæsar's friends should move the Council that day that Cæsar should be called king by the Senate." This inconsistency is not without parallels in Shakespeare. Cf. the "four strangers" in The Merchant of Venice, I, ii, 135, when six have been mentioned. In Scott, too, are many such inconsistencies.
[II.25] exhalations: meteors. In Plutarch's Opinions of Philosophers, Holland's translation, is this passage (spelling modernized): "Aristotle supposeth that all these meteors come of a dry exhalation, which, being gotten enclosed within a moist cloud, seeketh means, and striveth forcibly to get forth." Shakespeare uses 'meteor' repeatedly in the same way. So in Romeo and Juliet, III, v, 13.
[II.26] The Folios give this line as it is here. Some editors arrange it as the beginning of the letter repeated ponderingly by Brutus.
[II.27] dropp'd | dropt, F1F2.