to the commission by M. Broadfoot. The military domestics employed during the epidemic in the care of the sick were one hundred and sixty in number, and none of them had had yellow fever in any anterior epidemic. The civil domestics were sixtyone in number, and, with two exceptions, had already had the disease. These two, and these two only, amongst the last, had the disease, and forty of the military domestics, all the rest escaping. Other facts of a similar character were also presented to the commission. Slight and mild attacks of the disease seemed to be quite as preservative against its recurrence as grave and severe ones; and it did not appear that the protective effects were in any degree diminished by time.

Dr. Lewis has investigated this question with some care, and the result of his inquiries differs somewhat from that which I have just given. Five respectable citizens of Mobile, he says, have had the disease as many as three times, according to the testimony of competent judges. As many as twenty of his own patients, who were mildly attacked in 1843, stated that, according to their physicians, they had already had yellow fever during the epidemics of 1837 or 1839. Dr. Lewis concludes that, in 1843, about one-fifth of the patients who had mild yellow fever, had been subjects of the disease during previous epidemics. His opinion seems to be that, at least during the prevalence of grave epidemics, persons who have previously had the disease are, to a certain extent, liable to second attacks in a mild form.1

SEC. XI.-Epidemic Influences. Yellow fever usually prevails in a given locality more or less extensively; it becomes for the time being, as it is said, epidemic. The returns or recurrences of these epidemic seasons are altogether uncertain and irregular; they give no note of their coming; the laws which govern the revolutions of their periods are wholly unknown to us. One of the most remarkable and extensive of these large epidemic periods, was that which commenced in the year 1793, and continued for several years. I do not propose to go into any extensive or general enumeration of the epidemics whose histories have been preserved.

It has been said that the visitations of the disease, in New Or leans, had shown a tendency to observe alternate years; but an examination of the facts, as they have been published, during a continuous period of twenty-two years, from 1822 to 1843, both

IN. O. Med. and Surg. Journ., vol. i. p. 418.

included, gives but little support to this suggestion. From 1833 to 1841, the epidemic prevalence of the disease returned, with a good deal of regularity, on each alternate year; but from 1827 to 1830, and from 1841 to 1843, the disease prevailed regularly every year. According to Dr. Simons, the first appearance of yellow fever in Charleston, was in 1690 or 1700. It has since occurred in the following years, to wit: 1703, 1728, 1732, 1739, 1745, 1748, 1753, 1755, 1792, 1794, 1795, 1796, 1797, 1798, 1799, 1800, 1802, 1804, 1807, 1817, 1819, 1824, 1827, 1828, 1830, 1834, 1835, 1838, and 1839. Dr. Catel says that Martinique was almost entirely exempt from the disease, except a few sporadic cases, from 1828 to 1838.2

"That the essential cause of yellow fever," says Dr. Dowler, "will ever be discovered, or, being discovered, will be controlled or prevented by human art, is altogether improbable. Its mysterious cycles culminate, decline, and reappear. Charleston, desolated at the close of the seventeenth century, was exempt in the first quarter, but a sufferer in the second quarter of the eighteenth, and then, half a century of exemption again followed-a period much longer than that which now cheers the cities of New York, Philadelphia, Boston, and Baltimore, with the hope that yellow fever has taken its leave of them forever. But the last decennial period of the past century, and the first of the present, relumed the flames of the epidemic in Charleston, where they had smouldered so long, and in which they still continue to break out almost annually. Charleston suffered nearly a century in advance of New Orleans, and is still as great a sufferer as the latter." There is nothing in the past history of the disease at all incompatible with the probability that the elliptical sweep of its epidemic periods may again bring it within the more northern cities, from which, for many years, it has been absent.

SEC. XII.-Sporadic. Yellow fever, as I have just said, generally prevails in the form of an epidemic; but this is not always the

Am. Journ. Med. Sci., Feb., 1836. [The epidemic years in New York were 1702, 1741, 1742, 1748, 1791, 1794, 1795, 1796, 1797, 1798, 1799, 1800, 1801, 1803, 1805, 1819, 1822. The deaths from epidemic influences since 1805 at the highest estimate are two hundred and three; during the present century one thousand three hundred and ninety; and from 1748 to 1856 they appear not to have exceeded four thousand seven hundred and fifty to five thousand, though for some of the years the mortality is not definitely stated. Imported cases are seen almost every year in the city, but the disease does not spread.]

2 Rapport, &c., par M. Chervin, p. 6.

3 N. O. Med. Journ., vol. ii. p. 173.

case. It is now very well ascertained that yellow-fever cities are sometimes visited by isolated, sporadic cases of the disease. The question of the occurrence of the disease in this form was carefully studied by Louis and Trousseau, at Gibraltar, in 1828. Mr. Amiel and Mr. Fraser communicated to them the histories of forty-five cases, derived from the hospital registers, which had occurred dur ing non-epidemic seasons. Some of these cases Louis regards as spurious or doubtful; but he is quite confident of the genuineness of the others. Dr. Gillkrest says he is in possession of such a body of evidence, drawn from registers and other authentic sources at Gibraltar, as would of itself place the matter beyond all doubt. He adds that in the month of April, 1829, the records of the civil hospital in that garrison were examined, and a certificate drawn up and signed by nine gentlemen, to the effect that thirty-eight cases, of which they found details duly recorded in non-epidemic years, were identical in character with the cases which occurred there during the epidemic of 1828. Mr. Glasse, who was for a long time a resident at Gibraltar, says, in a letter to Dr. Burnett: "During the spring and autumn, I have been in the habit of seeing solitary cases of fever, attended with black vomiting and other severe symptoms."2

SEC. XIII.-Marsh Miasmata. Medical men, who look upon yellow fever as only a high grade, or concentrated and malignant form of bilious remittent fever, attribute the disease to the unknown cause or causes of the latter, called marsh miasmata, developed in unusual quantity, or endowed with extraordinary virulence. This is the opinion advocated by Dr. Bancroft in his elaborate treatise on the causes of this and other epidemic diseases, and by many others who believe in the local and domestic origin of the disease.

But the objections to this opinion are obvious and insuperable. In the first place, it is as well settled as any such question can be, that yellow fever differs, radically and essentially, from all the forms of periodic or marsh fever. The two diseases may prevail together, as marsh fevers and smallpox, or typhus, may; but in very extensive regions, where periodical fevers in their worst forms constitute the principal diseases, yellow fever is never seen. Again, in many yellow fever localities there is no evidence whatever of

1 Cyc. Prac. Med., vol. ii. p. 270.

2 Burnett, p. 329.

the existence of marshes, or marsh miasma. Dr. Gillkrest says: "It cannot be admitted that Gibraltar furnishes sources from which malaria, in the usual sense of that word, arises, sufficient to account for the appearance of a malignant fever." In 1844, yellow fever prevailed very extensively at Woodville, a small town in the interior of Mississippi. The town is built on a rolling ridge, three hundred and forty feet above the bank of the Mississippi River; the soil is clay and sand; the town is free from filth; and there are no swamps or ponds in the neighborhood. The island of Barbadoes is described as rocky and dry, with very little marshy or wet land. Brimstone Hill, in the island of St. Kitts, is a conical mount, rising to the height of seven hundred feet above the level of the surrounding plain. It is described as a volcanic rock, dry, nearly destitute of vegetation, and desolate in its entire aspect. It is generally free from yellow fever, but not uniformly so. In 1811 and 1812, the disease appeared there, and was very fatal. Stony Hill, in Jamaica, is thirteen hundred feet above the level of the sea. It is described as an entire mass of calcareous rock, covered with trees, excepting on the summit, but with little soil, and producing scarcely any grass or herbaceous plants. It is generally healthy; but yellow fever does sometimes prevail extensively and fatally amongst the troops stationed on its summit. Furthermore, the frequent occurrence of the disease in ships at sea is entirely incompatible with the doctrine of which I am now speaking; and the whole subject may be fairly and definitively dismissed, with an expression of surprise that the doctrine could ever have found any countenance or favor.

SEC. XIV. Decaying Animal and Vegetable Matter.- Filth. In the almost interminable discussion which has been going on during the last half century about the causes of yellow fever, there is no one element that has played a more prominent part than the decay or decomposition of animal and vegetable matter. Most of the advocates of what is called the domestic origin of the disease, and the deniers, at the same time, of its contagious properties, have attributed it principally to this animal and vegetable decomposition, and to various local accumulations of filth, of one kind and another. It is well known that the dreadful Philadelphia epidemic of 1793

Cyc. Prac. Med., vol. ii. p. 279. 3 Rush's Hillary, p. 5.

2 N. O. Med. Journ., vol. i. p. 530.

was referred, for its origin, by Dr. Rush, to a quantity of damaged coffee, decaying on one of the wharves of the city. The principal argument in favor of this opinion is the fact, generally admitted, that the disease most commonly commences in the low, crowded, and filthy quarters of yellow-fever cities, lying near the docks and wharves. Thus, the Bario de Santa Maria is usually the hot-bed of the disease in Cadiz. In 1795, at New York, the disease was mostly confined to the vicinity of Peck Slip, a crowded and filthy locality; and the same thing has occurred in other years. Dr. Edward Miller, of New York, one of the earliest and most unqualified advocates of the agency of filth in the production of yellow fever, says that, at the commencement of the destructive epidemic. of 1798, in that city, between twenty and thirty persons in a small neighborhood, at the lower end of John Street, were suddenly seized with the disease in one night, in consequence of a blast of putrid and most offensive exhalations from the sewer of Burling Slip.2

On the other hand, the agency of this cause is stoutly and boldly denied by many observers, and especially by those who believe in the contagious property, either qualified or absolute, of the disease. The principal objections to this doctrine are these: In the first place, it is asserted, and not denied, that yellow fever has sometimes made its appearance, and prevailed extensively, in localities quite free from any unusual accumulations of filth, either animal or vegetable. In the second place, it is quite notorious that, although the disease oftener than otherwise commences in filthy localities, still, it very frequently extends to the more airy and cleaner neighborhoods. In the third place, if the disease was generated from this source, it ought to occur with more regularity and constancy; since the alleged cause is always more or less extensively present and active, in some portions of all yellow-fever cities, and of others where the disease is never seen. It seems to me that these objections are quite unanswerable. Yellow fever occurred on board the United States schooner Grampus, in 1829. Dr. Barring ton says: "This vessel was remarkable for her uniform neatness and cleanly appearance throughout. The bilge-water smell was seldom perceived; the water coming out of the pumps perfectly clear." Several similar instances are mentioned by Dr. John

1 Hosack's Med. Essays, vol. i. p. 293. 2 Works of E. Miller, M. D., p. 98.

[See Sec. xviii. of this Chap.]

3 Amer. Journ. Med. Sci., Aug., 1833.