I shall here take occasion to remark, that the word _lutum_, in the line preceding the above passage of Virgil, must be translated _yellow-weed_, and not _woad_. The former, _Reseda luteola_, dyes yellow; but the latter, _Isatis_, dyes blue. _Lutum_, however, in Cæsar De bello Gallico, v. 14, seems to have been _woad_: “Omnes se Britanni luteo inficiunt, quod et cæruleum efficit colorem.” It appears, therefore, that both names were liable to be confounded in the Latin, as they are in the German; unless Davis be right, who, instead of _luteo_, reads _vitro_. That _sandyx_, in Virgil, signifies a plant rather than a mineral, is to me far more probable. The author speaks of plants which the sheep ate while feeding (_pascentes_); and both the above-mentioned dye-plants, yellow-weed and woad, grow wild in Italy. The opinion of Pliny, who understood the passage so, is not to be despised; and therefore the poetical account, that the pasture dyed the wool, is not altogether without foundation; especially as not only the roots, but also the leaves of madder, communicate a colour to the solid parts of animal bodies. I will however allow that most people readily fall into the error of being led away by imagination; and often suppose that they find in passages of ancient authors more than others can discover, or perhaps even than they contain. [275] Lib. xxiv. 9, p. 341. [276] The first account of this circumstance may be found in the Philosophical Transactions, vol. xxxix. n. 442, p. 287; n. 443, p. 299. Among the principal experiments made on this subject, are those of the Italian Matth. Bazanus, in Comment. Bononiens. and of J. H. Benj. Böhmer, in a dissertation entitled Radicis Rubiæ tinctorum effectus in Corpore Animali, Lips. 1751. Other works and observations relative to this singularity are mentioned in Haller’s Elementa Physiologiæ, v. p. 327.