fortune of a great number of powerful families, from their wealth, is at stake, will be by turns suspended and renewed without ever coming to a termination. At my passing through Vera Cruz, I saw the cabildo undertake to build a . new theatre, while at Mexico the assessor of the viceroy was composing a long informe, to prove the necessity of destroying the town, as being the seat of a pestilential disease. We have seen that in New Spain, as well as in the United States, the yellow fever not only attacks the health of the inhabitants, but also undermines their fortunes, either from the stagnation of interior trade, which it occasions, or by the obstacles which it throws in the way of foreign commerce. Hence, whatever relates. to this disease, interests the statesman as well as the observing naturalist. The insalubrity of the coast, which fetters commerce, facilitates in other respects the military defence of the country against the invasion of a European enemy; and to complete the political view of New Spain, it remains for us to examine the nature of the malady which renders the stay at Vera Cruz so formidable to the inhabitants of the cold and temperate regions. I shall not here enter into the details of a nosographical description of the vomito prieto. A great number of observations which I collected during my residence in the two hemispheres, is reserved

for the historical account of my travels; and I shall confine myself here to an indication of the most remarkable facts, distinguishing carefully the incontestible results of observation, from whatever belongs to physiological conjecture. The typhus, which the Spaniards designate by the name of black vomiting (vomito prieto) has long prevailed between the mouth of the Rio Antigua and the present port of Vera Cruz. The Abbe Clavigero" and some other writers, affirm that this disease appeared for the first time in 1725. We know not on what this assertion, which is so contrary to the traditions preserved among the inhabitants of Vera Cruz, is founded. No ancient document informs us of the first appearance of this scourge; for throughout all the warmer part of equinoctial America, where the termites and other destructive insects abound, it is infinitely rare to find papers which go fifty or sixty years back. It is believed however at Mexico as well as Vera Cruz, that the old town, now merely a village, known by the name of La Antigua, was abandoned towards the end of the 16th century t, on account of the disease which then carried off the Europeans. Long before the arrival of Cortez, there has

almost periodically prevailed in New Spain, an epidemical disease, called by the natives matlazahuatl, which several authors * have confounded with the vomito, or yellow fever. This plague is probably the same as that which in the eleventh century forced the Toltecs to continue their emigrations southwards. It made great ravages among the Mexicans in 1545, 1576, 1786, 1737, 1761, and 1762; but as we have already observed f, it differs essentially from the vomito of Vera Cruz. It attacked few except the Indians or copper-coloured race, and raged in the interior of the country on the central table land at twelve or thirteen hundred toises above the level of the sea. It is true, no doubt, that the Indians of the valley of Mexico, who perished by thousands in 1761, of the matlazahuatl, vomited blood at the nose and mouth; but these hematemeses frequently occur under the tropics, accompanying bilious ataxical (atariques) fevers; and they were also observed in the epidemical disease, which in 1759 prevailed over all South America, from Potosi and Oruro, to Quito and Popayan, and which from the incomplete description of Ulloaf was a typhus peculiar to the elevated regions of the Cordilleras. The physicians of the United

States who adopt the opinion that the yellow fever originated in the country itself, think they discover the disease in the pests which prevailed in 1535 and 1612 * among the red men of Canada and New England. From the little which we know of the matlazahuatl of the Mexicans, we might be inclined to believe, that in both Americas from the remotest periods, the coppercoloured race has been subject to a disease, which in its complications resembles in several respects the yellow fever of Vera Cruz and Philadelphia, but which differs essentially from it by the facility with which it is propagated in a cold zone, where the thermometer during the day remains at ten or twelve centigrade degrees, t It is certain that the vomito, which is endemical at Vera Cruz, Carthagena, and the Havannah, is the same disease with the yellow fever, which since the year 1793, has never ceased to afflict the inhabitants of the United States. This identity, against which a very small number of physicians in Europe have started doubts * is generally, acknowledged by those of the faculty who have visited the island of Cuba and Vera Cruz, as well as the coast of the United States, and by those who have carefully studied the excellent nosological descriptions of MM. Makittrick, Rush Valentin, and Luzuriaga. We shall not decide whether the yellow fever is perceptible in the causus of Hipocrates, which is followed, like several remittent bilious fevers, by a vomiting of black matter; but we think that the yellow fever has been sporadical in the two continents, since man born under a cold zone, have exposed themselves in the low regions of the torrid zone, to an air infected with miasmata. Wherever the exciting causes, and the irritability of the organs are the same, the disorders which originate from a disorder in the vital functions, ought to assume the same appearances. It is not to be wondered at, that, at a period when the communications between the Old and New Continent, were far from numerous, and when the number of Europeans who annually frequented the West India Islands, was still smaller, a disease which only attacks the individuals who are not seasoned to the climate, should have very little engaged the attention of the physicians of Europe. In the 16th and

* Arejula, de la fielre amarilla de Cadiz, t. i. p. 143.