The fact that this medieval treatise, whatever its exact date, was turned into English and circulated in manuscript, and that it was chosen for printing almost as soon as English printing began, in the reign of Edward IV., is sufficient evidence, if more were needed, that the English had to reckon with bubo-plague as one of their standing diseases throughout the latter part of the medieval period. Before we come to the chronology of English plagues in that period, from the Black Death to the accession of the Tudor dynasty in 1485, it will be convenient to consider here, with the help of the above treatise, how the endemic plague was viewed in those days,--what it was ascribed to in its origin, in its incidence upon houses and persons, and in its propagation, what was advised for its avoidance or prevention, and what was prescribed for its treatment. As the bishop’s essay was the source of most that was taught on these matters in England for the next two or three hundred years, it will be an economy to give a brief account of it here once for all. The remote causes, or warnings of the approach of pestilence, are given under seven heads, including the kind of weather, swarms of flies, shooting stars, comets, thunder and lightning out of the south, and winds out of the south; this list was reproduced, with little or no change, by the Elizabethan writers of popular health-manuals. The second section of the essay is on the “causes of pestilence.” There are three causes:-- “Sometime it cometh from the root beneath; other while from the root above, so that we may feel sensibly howwith change of the air appeareth unto us; and sometime it cometh of both together, as well from the root above as from the root beneath, as we see a siege or privy next to a chamber, or of any other particular thing which corrupteth the air in his substance and quality, which is a thing may happen every day. And thereof cometh the ague of pestilence (and about the same many physicians be deceived, not supposing this ague to be a pestilence). Sometimes it cometh of dead carrion, or corruption of standing waters in ditches or sloughs and other corrupt places. These things sometime be universal, sometime particular.” Then follow sentences on the “root above” which are somewhat transcendental. When both “roots” work together, when, by “th’ ynp‘ffyons[401]” above, the air is corrupt and by the putrefaction or rotten carrion of the vile places beneath,--an infirmity is caused in man. “And such infirmity sometimes is an ague, sometimes a posthume or a swelling, and that is in many things. Also the air inspired sometimes is venomous and corrupt, hurting the heart, that nature many ways is grieved, so that he perceiveth not his harm....