Pestilens est morbus contagiosus etc. As Ptolemy says, plague is a contagious sickness that people take one from the other. And Galen says also that plague is the aerial element turning from its proper moderation to corruption and putrefaction. For this is the cause of it: the evil-smelling putrescent air that rises from gross earthy vapours mixing with the thin parts of the air, or gross mist that rises from stagnant water such as ditches of the city and places
p.149where dwell toads(?) and venomous snakes and other poisonous animals. It also comes from an earthquake, and sometimes from the air of putrid bodies killed in fight or battle. And know, the more these bodies are in sympathy with(?) human bodies, so much the more they will die; and it comes from the warring of the heavenly bodies one with the other. It comes from the vengeance of God, and at another time from fruits and seeds and herbs of the earth, which become corrupt from the air we have mentioned. It is caused by perverse seasons as Ptolemy says; if the winter be hot and dry, without rain, the summer cold and wet, the spring cold and dry, and the autumn wet, there will be a great plague that year, acute fevers such as causon, tertian fever, causonides, sinocus and the like, along with bad accidents. And know, the plague caused by putrid moist vapours will kill fewer than the plague caused by putrid dry vapours.
It is asked here why pure thin air is best, for Galen says thin bright air is good for the maintenance of health, and that the blood and the spirits are purified by it; therefore pure air is good at this season. Item, everything that lessens and evacuates the corruption of the humours in general is to be recommended, therefore since pure transparent(?) air does these things, it is best. Item, Almansor says whenever the beasts of the earth leave their lairs and the places where they dwell underground, such as mice and weasels, stoats(?) badgers and rabbits; and the birds that are under the ground, such as bitterns and stonechats(?) leave their eggs and nests and flee from the corrupt vapours of the earth to the pure bright air, as Nature teaches them; hence since the nature of brutish beasts understands that pure air is the best, so human nature understands that it is best, and therefore pure air is best at this season. Item, Gilbert says if the spring be cold and wet, along with dark air and often with heavy, dark, black clouds, this signifies plague that year, therefore the contrary is best. Item, Hippocrates says everything that comforts the heart and expels its diseases such as syncope, cardiaca passio and the like is good; therefore since pure air exerts these powers it is best at this season. Item, Galen says the bodies that are purging themselves from their gross superfluities, such as phlegmatic people and melancholics, will be well at this season, therefore as it is pure air from which these powers are derived, it is best. Item, Galen says in the same place, everyone who has a complexion contrary to the complexion of the
p.150pestilential air, will not only be well at this season, but will be better than at any other; therefore since pure air is contrary to it, it is the best. This is opposed on the authority of Galen in the Book of Fevers, for he says moist, dark, gross air is best at this season; and it is proved, for every thin penetrating thing goes soonest to the heart and the organs of respiration, and every gross thing closes and blocks the pores, and the body does not take putrefaction or corruption from it; as such is gross air, therefore it is best.
Item, Magister Ricardus says everything that increases the sperm increases the humours in the body, such as cold foods like lettuce, melons, pomegranates, vinegar, ripe grapes, carrots(?) beet root, borrage, almond milk and the like, is good. Therefore since gross air fattens and increases these things, it is best. Item, the doctors say it behoves in time of plague to fly to glens and dark woods and other damp places, so according to this it is gross air that is best. Item, everything by which the body is purged, such as coition, hard labour, work at a forge, a dry bath or dry feeding (?) is bad at this season; according to this gross air is best. Item, everything that increases the spirits and prevents sleep, such as the smell of fragrant apples, ambergris, quinces, and lily flowers, the smell of mullen, and musk, nenufar flowers, violets, and sally-leaves, white rose flowers, and elder-blossoms, is good at this season; therefore since gross air does these things, it is best, as Johannes Mesue says.
Avicenna says in the first book, in the eighth chapter of perverse seasons that there are twelve rules that should be regarded in time of plague, concerning the seasons of the weather. The first rule: if the winter be cold and wet, and the wind frequently north, and the summer wet and windy, there will be a great plague amongst children the following autumn, and moreover flux of the belly, tertian fever, and ulceration of the guts i. e. dysentry, and the like. The second rule: if the winter be windy and wet, and the wind south, the spring dry and the wind NE. there will frequently be abortions and many other diseases among pregnant women that year; and there will also be disease of the eyes, bloody flux i. e. dysentery, and ague, scrofula, constriction of the nose and every sickness that comes from rheum particularly. The third rule: if the winter be dry and the wind NW., the spring wet and the wind frequently south, there will be acute fevers, disease of the
p.151eyes, flux of the belly and haemorrhage, the following summer there will be flux hepaticus i. e. a flux caused by the liver, and these plagues will greatly afflict women and men in whom a moist complexion is dominant. As Galen says, from moist superfluities are formed oppilations, and from oppilations is formed corruption in the gross humours that are not expelled at their proper times. The fourth rule: if the summer be windy and wet from the beginning of the days that are called Canicular, and then the wind to go to the north and remain there till the end of the same days, there will be cured thereby all cold diseases, such as quartan fever, dropsy, disease of the spleen, oppilation of the liver and cold diseases of the brain such as epilepsy, catalepsy, analepsy, apoplexy, subeth and the like. The fifth rule: if the summer be dry and the wind north, the autumn wet and the, wind south, there will be disease of the head, and coughs along with rupture of veins in the chest and hoarseness of the voice, and passage of rheum to the nose and the members in general the following winter. The sixth rule: if the summer be dry and the wind south, the autumn cold and the wind north, the following winter there will be headaches, noises in the ears, roughness of the voice, and passage of rheum to the limbs. The seventh rule: if the summer be cold and the wind south, the autumn dry and the wind north, there will be in the winter passage of rheum along with compression, with tightening on the brain, and imposthumes, and lumps on the lungs, and many other evil accidents. The eighth rule: if the summer and the autumn be wet and the wind frequently south, there will be a great plague and many other diseases the following winter. The ninth rule: when the summer and the autumn are dry and the wind north, it avails well for women and phlegmatic people, but it harms the folk of red bile and of black; and there will come dry disease of the eyes, ophthalmia, and acute fevers, frenesis and the like. The tenth rule: if the summer and the autumn be dry, and the winter cold and wet there will be disease of the urine that year i. e. suria(?) and disuria, stranguria, and burning and dryness of the membrum virile, ulcers on the bladder and the urinary passages. The eleventh rule: if the summer and the autumn be excessive in heat and dryness and the wind south usually, there will be quinsy, smallpox, measles and retention of urine, suppression of the menstrues, constriction of breath and the like. The twelfth rule: if the winter and the spring be dry, that year will be a bad
p.152one, and there will be want on man and beast and on the trees of the earth from the destruction and expulsion of the moisture of the ground, which should give softness, nourishment and moderation to it, through the dryness of the weather mentioned. And many other diseases will come that year.
It is clear here that every star and every other heavenly body has three risings i. e. (C)osmicus and (A)cronicus and (H)eliacus. This is Cosmicus: when a star or heavenly body rises under the sun to the east, and goes with it (the sun) until it sets on the west of the world. Acronicus moreover is when it rises to the west, and proceeds in company with the sun to walk the natural sphere which encircles the universe both land and sea, so that it sets to the east. And it is called acronicus from the word cronon, for cronon in Greek is the same as contrary in Gaelic, that is to say it rises in the west and finishes in the east. Heliacus moreover is when a star or heavenly body rises in the circle of the natural or material sphere on the horizon(?) and proceeds with the sun in the circle which is called Zodiac. And know, that this is Zodiac: the place where the sun is throughout the year, and it is divided into thirty degrees, and the sun is in each degree for thirty days and ten hours and a halfhour.