Dr. John Stedman has related many facts, in his Essay upon Insalutary Constitutions of the Air, which prove, that diseases are influenced by a quality in it, which, he says, “is productive of corruption,” but which has hitherto eluded the researches of physicians[41].
Mr. Lempriere, after mentioning the unusual mortality occasioned by the yellow fever, within the last five or six years, in the island of Jamaica, ascribes it wholly “to that particular constitution of atmosphere upon which the existence of epidemics, at one period rather than another, depend[42].”
Not only diseases bear testimony to a change in the atmosphere, but the whole vegetable and animal creation concur in it, proofs of which were mentioned in another place. Three things are remarkable with respect to this inflammatory constitution of the air.
1. It is sometimes of a local nature, and influences the diseases of a city, or country, while adjoining cities and countries are exempted from it.
2. It much oftener pervades a great extent of country. This was evident in the years 1793 and 1794, in the United States. During the same years, the yellow fever prevailed in most of the West-India islands. Many of the epidemics mentioned by Dr. Sims, in the first volume of the Medical Memoirs, affected, in the same years, the most remote parts of the continent of Europe. Even the ocean partakes of a morbid constitution of its atmosphere, and diseases at sea sympathise in violence with those of the land, at an immense distance from each other. This appears in a letter from a surgeon, on board a British ship of war, to Mr. Gooch, published in the third volume of his Medical and Surgical Observations.
3. The predisposing state of the atmosphere to induce malignant diseases continues for several years, under all the circumstances of wet and dry, and of hot and cold weather. This will appear, from attending to the accounts which have been given of the weather, in all the years in which the yellow fever has prevailed in Philadelphia since 1792[43]. The remark is confirmed by all the records of malignant epidemics.
It is to no purpose to say, the presence of the peculiar matter which constitutes an inflammatory or malignant state of the air has not been detected by any chemical agents. The same thing has been justly said of the exhalations which produce the bilious intermitting, remitting, and yellow fever. No experiment that has yet been made, has discovered their presence in the air. The eudiometer has been used in vain for this purpose. In one experiment made by Dr. Gattani, the air from a marsh at the mouth of the river Vateline was found to be apparently purer by two degrees than the air on a neighbouring mountain, which was 2880 feet higher than the sea. The inhabitants of the mountain were notwithstanding healthy, while those who lived in the neighbourhood of the marsh were annually afflicted with bilious and intermitting fevers[44]. The contagions of the small-pox and measles consist of matter, and yet who has ever discovered this matter in the air? We infer the existence of those remote causes of diseases in the atmosphere only from their effects. Of the existence of putrid exhalations in it, there are other evidences besides bilious and yellow fevers. They are sometimes the objects of the sense of smelling. We see them in the pale or sallow complexions of the inhabitants of the countries which generate them, and we observe them occasionally in the diseases of several domestic animals. The most frequent of these diseases are inflammation, tubercles, and ulcers in the liver. Dr. Cleghorn describes a diseased state of that viscus in cattle, in an unhealthy part of the island of Minorca. Dr. Grainger takes notice of several morbid appearances in the livers of domestic animals in Holland, in the year 1743. But the United States have furnished facts to illustrate the truth of this remark. Mr. James Wardrobe, near Richmond, in Virginia, informed me, that in August, 1794, at a time when bilious fevers were prevalent in his neighbourhood, his cattle were seized with a disease, which, I said formerly, is known by the name of the yellow water, and which appears to be a true yellow fever. They were attacked with a staggering. Their eyes were muddy, or ferocious. A costiveness attended in all cases. It killed in two days. Fifty-two of his cattle perished by it. Upon opening the bodies of several of them, he found the liver swelled and ulcerated. The blood was dissolved in the veins. In the bladder of one of them, he found thirteen pints of blood and water. Similar appearances were observed in the livers of sheep in the neighbourhood of Cadiz, in the year 1799, during the prevalence of the yellow fever in that city. They were considered as such unequivocal marks of an unwholesome atmosphere among the ancients, that they examined the livers of domestic animals, in order to determine on the healthy or unhealthy situation of the spot on which they wished to live.
The advocates for the yellow fever being a specific disease, and propagated only by contagion, will gain nothing by denying an inflammatory constitution of the atmosphere (the cause of which is unknown to us) to be necessary to raise common remittents to that grade in which they become malignant yellow fevers; for they are obliged to have recourse to an unknown quality in the air, every time they are called upon to account for the disease prevailing chiefly in our cities, and not spreading when it is carried from them into the country. The same reference to an occult quality in the air is had by all the writers upon the plague, in accounting for its immediate and total extinction, when it is carried into a foreign port.
In speaking of the influence of an inflammatory constitution of the atmosphere in raising common bilious, to malignant yellow fevers, I wish not to have it supposed, that its concurrence is necessary to produce sporadic cases of that, or any other malignant disease. Strong exciting causes, combined with highly volatilized and active miasmata, I believe, will produce a yellow fever at any time. I have seen one or more such cases almost every year since I settled in Philadelphia, and particularly when my business was confined chiefly to that class of people who live near the wharves, and in the suburbs, and who are still the first, and frequently the only victims of the yellow fever.