[272] Thucyd. ii, 52; Diodor. xii, 45; Plutarch, Periklês, c. 34. It is to be remarked, that the Athenians, though their persons and movable property were crowded within the walls, had not driven in their sheep and cattle also, but had transported them over to Eubœa and the neighboring islands (Thucyd. ii, 14). Hence they escaped a serious aggravation of their epidemic: for in the accounts of the epidemics which desolated Rome under similar circumstances, we find the accumulation of great numbers of cattle, along with human beings, specified as a terrible addition to the calamity (see Livy, iii, 66; Dionys. Hal. Ant. Rom. x, 53: compare Niebuhr, Römisch. Gesch. vol. ii, p. 90). [273] Thucyd. ii, 49. Τὸ μὲν γὰρ ἔτος, ὡς ὡμολογεῖτο, ἐκ πάντων μάλιστα δὴ ἐκεῖνο ἄνοσον ἐς τὰς ἄλλας ἀσθενείας ἐτύγχανεν ὄν. Hippokratês, in his description of the epidemic fever at Thasos, makes a similar remark on the absence of all other disorders at the time (Epidem. i, 8, vol. ii, p. 640, ed. Littré). Of this plague,—or, more properly, eruptive typhoid fever,[274] distinct from, yet analogous to, the smallpox,—a description no less clear than impressive has been left by the historian Thucydidês, himself not only a spectator but a sufferer. It is not one of the least of his merits, that his notice of the symptoms, given at so early a stage of medical science and observation, is such as to instruct the medical reader of the present age, and to enable the malady to be understood and identified. The observations, with which that notice is ushered in, deserve particular attention. “In respect to this distemper (he says), let every man, physician or not, say what he thinks respecting the source from whence it may probably have arisen, and respecting the causes which he deems sufficiently powerful to have produced so great a revolution. But I, having myself had the distemper, and having seen others suffering under it, will state _what it actually was_, and will indicate, in addition, such other matters, as will furnish any man, who lays them to heart, with knowledge and the means of calculation beforehand, in case the same misfortune should ever again occur.”[275] To record past facts, as a basis for rational prevision in regard to the future,—the same sentiment which Thucydidês mentions in his preface,[276] as having animated him to the composition of his history,—was at that time a duty so little understood, that we have reason to admire not less the manner in which he performs it in practice, than the distinctness with which he conceives it in theory. We may infer from his language that speculation in his day was active respecting the causes of this plague, according to the vague and fanciful physics and scanty stock of ascertained facts, which was all that could then be consulted. By resisting the itch of theorising from one of those loose hypotheses which then appeared plausibly to explain everything,