fine, toward the decline of the difeafe, when the inflammation is abated, it will be proper to purge the patient gently.

But I must not omit to take notice, that a puru, lent abfcefs or empyema, from an inflammation of the exteriour membrane of the lungs, and its adhesion to the pleura, is fometimes formed in this disease; and more frequently ftill in a peripneumony. In this cafe, if the tumour points outward, a cauftic should be applied to it, to let out the matter: and the ulcer is to be kept open during life. For I have feen inftances, where, upon healing it up, and confequently ftopping the drain, the patient died in a little time,

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SECTION VIII.

of intermitting fevers.

"Hat an intermitting fever is not carried off by the Peruvian bark with a proper degree of certainty, without premising a vomit or a purge, or both, is not unknown to physicians; but to join fome mild cathartic to this remedy, will perhaps appear new in practice. For it is commonly thought among us, that this medicine has little or no effect, unless the patient be coftive, while he takes it. But long experience has taught me, that it is quite neceffary to add a finall quantity of rhubarb to this febrifuge; fo as to procure two ftools at least every day. Nor have I ever observed, that this procedure has leffened its virtue, but rather rendered it more efficacious. For although strong irritating cathartics raife fuch dif turbances in the blood and humours, as make the proper medicines ineffectual: yet moderate purging

is attended with this good effect, that the ftomach better digefts whatever is taken in, whether medicines or food; whereby their fineft and moft wholefome parts pafs into the mafs of blood.

The occafion of my contriving this method of giving the bark was this. Near twenty years ago intermittent fevers, of a worfe fort than ordinary, were very rife, and frequently terminated in a bad habit of body, and even in a dropfy; which confequences when I had maturely confidered, I thought, that this method might probably guard against them; nor was I deceived in my opinion, And the fuccefs with which it was attended, encouraged me to purfue it, whenever this difeafe attacked bodies loaded with grofs humours. But I was well aware of the danger of purging too much. Wherefore my cuftom is, after having given a drachm or two of rhubarb in this manner, to omit the purgative, and continue the use of the febrifuge alone. And befides the advantages already recited, I made this obfervation, that when the difeafe is carried off by this method, there is always lefs danger of a relapse.

Now, with regard to this noble medicine, I have this one admonition to give, that it is not proper in any other fevers but thofe of the intermittent kind. For in continuals, it is fo far from being of service, that it does much mischief; and it is pernicious alfo in thofe hectics, which are accompanied with ulcers of any of the internal parts; though they often have periodical returns, and much refemble quotidian or tertian intermittents. Whence it may not perhaps appear an improbable conjecture, that this medicine. operates on the bile alone; for that the bile has a

confiderable

confiderable share in caufing intermitting fevers, I have not the leaft doubt.

However, it fometimes happens, that this febrifuge fails in true intermittents; which failure is generally owing to a bad habit of body. Wherefore the phyfician fhould ufe his beft endeavours to discover in what part the fault lies; and it will be commonly found to be in the vifcera and glands of the abdomen. Upon this account it will be neceffary to prescribe fome purges, and fometimes vomits; and in the intermediate days deobftruents and ftomachics, the best of which are aromatic bitters and preparations of steel. And for the fame reafon it is, that quartans are of more difficult cure than any other intermittents: for in these the blood and humours are inert and exceffively vifcid; fo that there are two diseases to be conquered together, the bad habit of body, and the fever which is generally done effectually, by joining Virginia fnake-root and fteel with the bark. However, it may not be improper to take notice, that in fome cafes where the bark did not answer, I have taken off intermitting fevers with a powder compofed of chamomile-flowers, myrrh, falt of wormwood, and a little alum.

But there is more danger attending that fort of intermitting fever, by the Greeks named Tgratos, that is, femitertian. This fever returns every third day; and of forty-eight hours the fit commonly takes up about thirty-fix, more or lefs; nor does the fever go off entirely, but only remits between the paroxyfms. -Hence Galen was right in faying, that it was comVOL. III. pounded

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pounded of a continual quotidian and an intermitting tertian *.

Thus a particular regard is due to this disease, which feems to be caufed by an inflammation of fome internal parts, accompanied with obftructions from bilious humours and too vifcid lymph. Wherefore blood is to be drawn once or oftener, according to the patient's ftrength: and gentle purgatives, fuch as the diuretic falt, manna with Glauber's falt, and the like, are to be ordered and repeated at proper diftances of time. Nor ought we to be hafty in giving the bark, for fear it should increase the inflammation by adding to the obstruction of the vifcera, and bring on a hectic. It will be much fafer, firft, to order the falime draughts, with juice of lemons, falt of wormwood, and fimple cinnamon-water, to be taken frequently.

SECTION IX.
Of epidemic fevers.

Epidemic fevers are caused by fome fault in our

ambient air; and that is chiefly owing to the excefs of heat, cold, drought, or moisture, or to the unfeafonable viciffitudes of thefe qualities.

In Greece and Afia, where the feafons are generally uniform, and the winds pretty regular from certain but different quarters in the different months of the year, it was eafy for men of fagacity to obferve the changes of the weather, with their good and bad effects. And on a long ufe of this method of obfervation was built the art of prognoftic in difeafes;

* De different. febr. lib. ii. cap. 7.

wherein

wherein Hippocrates the father of phyfic firft excelled. But in our climates, fuch is the inconftancy of the weather, and fo many are the caufes that raife different and even contrary winds on a fudden, that it feems impoffible to erect any folid fuperftructure on that foundation. And accordingly Sydenham, who, in imitation of Hippocrates, attempted to defcribe the feyers of each refpective year, and to account for their differences from the difference of the weather and feafons, found at length," that he had made no progrefs in difcovering the causes of epidemical dif"eafes by obferving the manifeft qualities of the air:

as having remarked, that in different years, which "agreed perfectly well in the vifible temperature of

the air, the reigning diseases were very different, " and fo on the contrary and likewife that there are " various constitutions of years, which depend not on

heat, cold, drought, or moisture, but on fome "occult and inexplicable alteration in the very bowels "of the earth *"

Now, this matter, in my opinion at least, ftands thus: that the manifeft qualities of the air have a confiderable share in producing epidemic difeafes, is a point that admits of no doubt; but there are other conjunct caufes, which alter the force of thofe qualities, either by increafing or diminishing them. These chiefly fpring from the earth, as Lucretius wifely faid,

-ubi putrorem humida nacta eft, Intempeftivis pluviifque et folibus icta †.

* Obf. med. cap. ii. de morbis epidemicis. vi. ver 1099.

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+ Lib.

When