l. 8. _Remoraes_; Browne doubts 'whether the story of the remora be not unreasonably amplified'. The name is given to any of the fish belonging to the family Echeneididae, which by means of a suctorial disk situated on the top of the head adhere to sharks, other large fishes, vessels, &c., letting go when they choose. The ancient naturalists reported that they could arrest a ship in full course. See Bartholomaeus Anglicus, Lib. xiii, _De Aqua et ejus Ornatu_. l. 11. _the even line_ is the reading of all the MS. copies, and must have been taken from one of these by the 1669 editor. The use of the word is archaic and therefore more probably Donne's than an editor's emendation. Compare Chaucer's 'Of his stature he was of even length', i.e. 'a just mean between extremes, of proper magnitude or degree'. The 'even line' is, as the context shows, the exact mean between the 'adverse icy poles'. I suspect that 'raging' is an editorial emendation. There are several demonstrable errors in the 1633 text of this poem. The 'other' of _P_, and 'over' of _S_, are errors which point to 'even' rather than 'raging'. l. 12. _th'adverse icy poles._ The 'poles' of most MSS. is obviously necessary if we are to have _two_ temperate regions. The expression is a condensed one for 'either of the adverse icy poles'. Compare: He that at sea prayes for more winde, as well Under the poles may begge cold, heat in hell. One cannot be under both the poles at once. One is 'under' the pole in Donne's cosmology because the poles are not the termini of the earth's axis but of the heavens'. 'For the North and Southern Pole, are the invariable terms of that Axis whereon the Heavens do move.' Browne, _Pseud. Epidem._ vi. 7. Tristior illa Terra sub ambobus non iacet ulla polis. Ovid, _Pont._ ii. 7. 64. l. 17. _Can dung and garlike, &c._ This is the text of the 1633 edition made consistent with itself, and it has the support of several MSS. Clearly if we are to read 'or' in one line we must do so in both, and adopt the _1635-69_ text. It is tempting at first sight to do so, but I believe the MSS. are right. What Donne means is, 'Can we procure a perfume, or a medicine, by blending opposite stenches or poisons?' This is his expansion of the question, 'Shall cities, built of both extremes, be chosen?' The change to 'or' obscures the exact metaphysical point. It would be an improvement perhaps to bracket the lines as parenthetical.