The precise days of its eruption in the individual towns, are no longer to be ascertained; but it was not simultaneous: for in Florence, the disease appeared in the beginning of April;[53] in Cesena, the 1st of June;[54] and place after place was attacked throughout the whole year; so that the plague, after it had passed through the whole of France and Germany, where, however, it did not make its ravages until the following year, did not break out till August, in England; where it advanced so gradually, that a period of three months elapsed before it reached London.[55] The Northern Kingdoms were attacked by it in 1349. Sweden, indeed, not until November of that year: almost two years after its eruption in Avignon.[56] Poland received the plague in 1349, probably from Germany,[57] if not from the northern countries; but in Russia, it did not make its appearance until 1351, more than three years after it had broken out in Constantinople. Instead of advancing in a north-westerly direction from Tauris and from the Caspian Sea, it had thus made the great circuit of the Black Sea, by way of Constantinople, Southern and Central Europe, England, the Northern Kingdoms and Poland, before it reached the Russian territories; a phenomenon which has not again occurred with respect to more recent pestilences originating in Asia. [53] _Matt. Villani_, Istorie, in _Muratori_, T. XIV. p. 14. [54] Annal. Caesenat, _Ibid._ p. 1179. [55] _Barnes._ Loc. cit. [56] _Olof Dalin’s_, Svea-Rikes Historie, III. vol. _Stockholm_, 1747–61, 4. Vol. II. C. 12, p. 496. [57] _Dlugoss_, Histor. Polon. L. IX. p. 1086, T. I. _Lips_. 1711, fol. Whether any difference existed between the indigenous plague, excited by the influence of the atmosphere, and that which was imported by contagion, can no longer be ascertained from the facts; for the contemporaries, who in general were not competent to make accurate researches of this kind, have left no data on the subject. A milder and a more malignant form certainly existed, and the former was not always derived from the latter, as is to be supposed from this circumstance--that the spitting of blood, the infallible diagnostic of the latter, on the first breaking out of the plague, is not similarly mentioned in all the reports; and it is therefore probable, that the milder form belonged to the native plague,--the more malignant, to that introduced by contagion. Contagion was, however, in itself, only one of many causes which gave rise to the Black Plague.