In order to give you the most regular account of this disorder I could procure, I must repeat several circumstances from former letters.
The yellow fever, which has lately been so fatal, is a new disorder, first brought to the West Indies, in a slave-ship from the coast of Africa, late in the year 1792. It spread rapidly from island to island, and in July, 1793, was first imported to the continent in a french schooner to Philadelphia. The physicians of that city, naturally concluding it was the usual yellow fever of the West Indies, applied the common remedies in that case: viz., bark, and other astringents. In nine cases out of ten, death was the inevitable consequence to all who took these medicines. The disease was equally fatal to the faculty. A universal despondency took place, till doctor Rush, suspecting this was a new disorder, applied an opposite method of cure, by mercurial medicines, and copious bleedings; which, when administered in the first or second stage of the disorder, had the desired effect.
I send you an extract from the doctor's pamphlet, wherein he explains his motives for adopting this method of cure, &c.
Speaking of the effect of the lancet, he says, "It was at this time my old master reminded me of Dr. Sydenham's remark, that moderate bleeding did harm in the plague, where copious bleeding was indicated, and that, in the cure of that disorder, we should leave Nature wholly to herself, or take the cure altogether out of her hands."
The truth of this observation was obvious:—By taking away as much blood as restored the blood-vessels to a morbid degree of action, without reducing this action afterward, pain, congestion, and inflammation, were greatly increased; all of which were prevented, or occurred in a less degree, when the system rose gradually from the state of depression which had been induced by indirect debility. Under the influence of the facts and reasonings which have been mentioned, I bore the same testimony in acute cases against what was called moderate bleeding, that I did against bark, wine, and laudanum, in this fever.—I drew from many persons seventy or eighty ounces of blood in five days.
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After the cold weather had completely destroyed this disorder, it did not appear again in the United States till the next year, when it was imported to Baltimore and New Haven; a distance from each other of more than five hundred miles. The cold weather again destroyed it, till carried, in 1795, to Charleston and New York, equally distant from each other; and this summer it was imported to Charleston, New York, Boston, and Newbery Port; a distance of one thousand five hundred miles along the coast; but fortunately the early N.W. winds destroyed it in all these places before it had made any considerable progress.
A quarantine upon vessels from the infected islands would effectually prevent the importation of this plague; but if performed in the literal sense of the word, it would materially hurt the West India trade of the Americans.
You have little to fear from this disorder being brought to England; experience has clearly proved, this fever cannot exist in a cold climate; but was it to be imported to the south of Europe, the consequences would be dreadful indeed. I before told you, the negroes were not afflicted with the yellow fever, though universally employed as nurses to the sick.
A disease that will affect but one species of men is not new. About the year 1652, a very dreadful and uncommon plague ravaged this part of America, and actually extirpated several nations of the Indians, without, in a single instance, affecting the white emigrants, though continually among them. This strange circumstance the fanatics of New England accounted for in their usual way, as appears from several of their sermons, still preserved:—