[II.28] See quotation from Plutarch in [note, p. 40, l. 143].
[II.29] What, Rome? Rowe | What Rome Ff.
[II.30] ancestors Ff | ancestor Dyce.
[II.31] thee F1F4 | the F2F3.
[II.32] fifteen Ff | fourteen Theobald.
[II.33] fifteen. This, the Folio reading, is undoubtedly correct. Lines 103-104 and 192-193 show that it is past midnight, and Lucius is including in his computation the dawn of the fifteenth day, a natural thing for any one to do, especially a Roman.
[II.34] ll. 60, 76: [Exit Lucius] Ff omit.
[II.35] motion: prompting of impulse. Cf. King John, IV, ii, 255.
[II.36] phantasma: a vision of things that are not. "Shakespeare seems to use it ('phantasma') in this passage in the sense of nightmare, which it bears in Italian."—Clar. What Brutus says here is in the very spirit of Hamlet's speeches. Cf. also the King's speech to Laertes, Hamlet, IV, vii, 115-124, and Macbeth, I, vii, 1-28.
[II.37] Commentators differ about 'Genius' here; some taking it for the 'conscience,' others for the 'anti-conscience.' Shakespeare uses 'genius,' 'spirit,' and 'demon,' as synonymous, and all three, apparently, both in a good sense and in a bad, as every man was supposed to have a good and a bad angel. So, in this play, [IV, iii, 282], we have "thy evil spirit"; in The Tempest, IV, i, 27, "our worser genius"; in Troilus and Cressida, IV, iv, 52, "some say the Genius so Cries 'come' to him that instantly must die"; in Antony and Cleopatra, II, iii, 19, "Thy demon, that's thy spirit which keeps thee"; where, as often, 'keeps' is 'guards.' In these and some other cases the words have some epithet or context that determines their meaning, but not so with 'Genius' in the text. But, in all such cases, the words indicate the directive power of the mind. And so we often speak of a man's 'better self,' or a man's 'worser self,' according as one is in fact directed or drawn to good or to evil.—The sense of 'mortal' here is also somewhat in question. Shakespeare sometimes uses it for 'perishable,' or that which dies; but oftener for 'deadly,' or that which kills. 'Mortal instruments' may well be held to mean what Macbeth refers to when he says, "I'm settled, and bend up Each corporal agent to this terrible feat."—As Brutus is speaking with reference to his own case, he probably intends 'Genius' in a good sense, for the spiritual or immortal part of himself. If so, then he would naturally mean by 'mortal' his perishable part, or his ministerial faculties, which shrink from executing what the directing power is urging them to. The late Professor Ferrier of St. Andrews seems to take a somewhat different view of the passage. He says, "In this speech of Brutus, Shakespeare gives a fine description of the unsettled state of the mind when the will is hesitating about the perpetration of a great crime, and when the passions are threatening to overpower, and eventually do overpower, the reason and the conscience."