f

own precipitancy, and fuperficial obfervation. The man in reality, who pretends to cure a fever, without a knowledge of the critical periods of nature, is not less presumptuous, than the mariner, who undertakes to condu& a veffel through the ocean, without being inftructed in the manner of calculating her course.

CHAP.

CHAP. IV.

OF THE GENERAL REMOTE CAUSES OF INTERMITTING AND REMITTING

FEVERS.

THE general remote caufes of intermitting and remitting fevers have been fo fully investigated by feveral eminent writers, particularly by the induftrious and learned Lancifi, that little remains to be added: nor perhaps fhould I have thought it necessary, even to have mentioned the fubject, were it not to take notice of fome opinions of the late Sir John Pringle, which appear to have been formed too precipitately; and which, I can affirm from experience, have been pernicious. to the health of thousands. It would be a very needless oftentation to adduce the authority of the ancients, to prove the general fource of the difeafe which is the fubject of the present treatise. The hiftorians, no less than the phyficians of every age, do not entertain a doubt, that fevers of the intermitting and remitting kind, owe their origin to exhalations from fwampy and moift grounds.

Daily experience ftill proves it; and there are few men whofe obfervations are fo circumscribed, as not to know, that it is in the neighbourhood of fwamps, and near the banks of fresh water rivers, that those diforders chiefly prevail. But though it is only in the above fituations, that intermitting and remitting fevers are more peculiarly epidemic; yet it likewise deserves to be remarked, that, independent of the particular circumstances of foil and local fituation, the endemic of all champaign countries is fubject, in a greater or less degree, to an appearance of periodical revolution. Mud and stagnant water, in every climate, poffefs the materials of the cause of this fpecies of disease; but a combination of other circumftances is required to give them activity. Among the principal of those circumstances, which call forth this action, we may reckon the influence of a powerful fun. Hence, (as is commonly known), fome fituations, which, in the colder months of winter, are distinguished for no particular disease, in the hot months of fummer and autumn, are obferved to be moft malignantly unhealthful.

The nature of this exhalation or caufe of fever, though it has long been a fubject of enquiry, remains ftill unknown. We plainly perceive it to be of various degrees of force,

and

and in various ftates of concentration; and we can easily conceive it to be variously modified and combined;--but we go no farther. It has been faid, to poffefs a feptic principle; but this alone will scarcely be thought fufficient, to account for the very peculiar manner in which it affects the human race. Some other quality is neceffarily joined with it, which our fenfes cannot lay hold of. But though the ingenuity of man has not hitherto been able to penetrate the intimate nature of this caufe of fever, we ftill have it in our power, in fome degree, to trace its effects on the human conftitution. We plainly perceive that an habitual exposure to it, is peculiarly unfriendly to the principle of life, and in a very remarkable manner shortens the period of existence. In proof of this I mention from good authority, that white females, born and constantly refiding in the lower districts of the province of Georgia in America, have feldom been obferved to live beyond the age of forty. Males, fometimes approach near to fifty; while Europeans, who had arrived at manhood before they came to the country, often attain a good old age. The fact is curious, and fhews, in a strong point of view, the deleterious quality of the air of those climates. But though the general nature of the

country,

country, which I have just now mentioned, is unhealthy in a high degree; yet there are fituations, in the Carolinas and Virginia, which are deftructive of life in a ftill more remarkable manner. There is not on record, I am credibly informed, an instance of a perfon born at Petersborough in Virginia, and conftantly refiding in the fame place, who has lived to the age of twenty-one. When the British army marched through this province, in the year 1781, I had the opportunity of feeing a native of this town, who was then in his twentieth year; but he was faid to be the firft, who had ever attained fo advanced an age. He was decrepid, as if from the effects of time, and it did not appear that he could furvive many months. Yet it is not a little curious, that this man had never been much confined with fickness. The refiding conftantly in the fame pernicious air, feemed alone to have been fufficient fo remarkably to accelerate decrepitude. But though the inftances I have mentioned afford fufficient proof, that this miafma is unfriendly to the principle of life; yet we are by no means instructed, as to the manner, by which it becomes fo. This feems to be one of the arcana of nature; and it will profit little to profecute it farther by conjecture. It will, how