generally believed, that a squadron from Siam introduced the vomito into America*.

In all climates men appear to find some consolation in the idea that a disease considered as pestilential is of foreign origin. As malignant fevers easily originate in a numerous crew cooped up in dirty vessels, the beginning of an epidemic may be frequently traced to the period of the arrival of a squadron; and then instead of attributing the disease to the vitiated air contained in vessels deprived of ventilation, or to the effects of an ardent and unhealthy climate on sailors newly landed, they affirm, that it was imported from a neighbouring port, where a squadron or convoy touched at, during its navigation from Europe to America. Thus we frequently hear in Mexico, that the ship of war which brought such or such a viceroy to Vera Cruz, has introduced the yellow fever, which for several years had not prevailed there; and in this manner during the season of great heat, the Havannah, Vera Cruz, and the ports of the United States mutually accuse one another of communicating the germ of the contagion.

It is with the yellow fever as with

* Labat's Voyage aux Isles, T. i. p. 73. Respecting the plague of Boullam in Africa, see Chisholm on Pestilential Fever, p. 61; Miller, Histoire de la fievre de New Yorck, p. 61; and Volney, Tableau du Sol de l'Amerique, T. ï. p. 334.

the mortal typhus, known by the name of oriental pest, which the inhabitants of Egypt attribute to the arrival of Greek vessels, while in Greece and Constantinople, the same pest is considered as coming from Rosetta or Alexandria *.

Pringle, Lind, and other distinguished physicians consider our summer and autumnal bilious affections, as the first degree of yellow fevert. A feeble analogy is also discoverable in the pernicious intermittent fevers which prevail in Italy, and which have been described by Lancisi Torti, and recently by the celebrated Franck in his treatise of general nosology (nosographie). It is affirmed that from time to time in the Campagna di Roma, individuals have been seen to die with nearly all the pathognomonical signs of yellow fever, icterus, vomiting, and hemorrhages. Notwithstanding these resemblances which are not acci

* Pugnet, sur les fievres du Levant et des Antilles, p. 97 and 331.

+ Lind sur les maladies des Europeens, dans les pays chauds, p. 14; Berthe, Precis historique de la maladie qui a regné en Andalousie, en 1800, p. 17.

i.

p.

Petrus Franck de curandis hominum morbis, T. 150. The analogy observable between the cholera morbus, the bilious fever and the gastro adynamical fever, has been indicated with much sagacity in the beautiful work of M. Pinel, Nosographie Philosophique, (3rd edition) T. i. p. 46

and 47.

dental, we may consider the yellow fever wherever it assumes the character of an epidemical disease, as a typhus sui generis, which participates both of the gastric and ataxo-adynamical fevers *. We shall distinguish consequently the bilious stationary fevers, and the intermittent pernicious fevers which prevail on the banks of the Orinoco, on the coast which extends from Cumana to Cape Codera, in the valley of the Rio de la Magdalena, at Acapulco, and in a great number of other humid and unhealthy places visited by us, from the vomito prieto, or yellow fever, which exerts its ravages in the West Indies, at New Orleans, and Vera Cruz.

The vomito prieto, has never appeared hitherto on the western coast of New Spain. The inhabitants of the coast, which extends from the mouth of the Rio Papagallo, by Zacatula and Colima, to San Blas, are subject to gastric fevers, which frequently degenerate into adynamical fevers; and we might say that a bilious constitution prevails almost continually in these arid and burning plains intersected with small marshes, which serve for abodes to the crocodiles t.

Nosographie', T. i. p. 139-152, and p. 209. Mr. Franck designates the yellow fever by the name of febris gastrico

nervosa.

+ Crocodilus aquitus.--Cuv.

At Acapulco, bilious fevers and the cholera morbus are very frequent; and the Mexicans who descend from the table land to purchase goods on the arrival of the galleon, are but too frequently the victims of them. We have already described the position of that town, the unfortunate inhabitants of which, tormented with earthquakes and hurricanes, breathe a burning air, full of insects, and vitiated by putrid emanations. For a great part of the year they perceive the sun only through a bed of vapours of an olive hue, which do not affect the hygrometer placed in the lower regions of the atmosphere. On comparing the plans which I have given of the two towns in my atlas of New Spain, we may easily conjecture that the heat must be still more oppressive, the air more stagnant, and the existence of man more painful at Acapulco, than at Vera Cruz. In the former of these two places, as well as at Guayra and Santa Cruz in Teneriffe, the houses are built against a wall of rock which heats the air by reverberation. The basin of the port is so surrounded with mountains, that to give during the heats of summer some opening to the sea wind, Colonel Don Josef Barriero, Castellano or governor of the Castle of Acapulco, caused a cut to be made through the mountain. This bold undertaking which goes in the country by the name of Abra de San Nicolas, has not

The

been without utility. Obliged during my residence at Acapulco to pass several nights in the open air for the purpose of making astrono mical observations, I constantly felt for two or three hours before sun-rise, when the temperature of the sea was very different from that of the Continent, a small current of air which entered by the breach of San Nicolas. This current is the more salutary, as the atmosphere of Acapulco is poisoned by the miasmata which exhale from a marsh called the cienega del castillo, situated to the east of the town. stagnant water of this marsh disappears every year, which occasions the death of an innume rable quantity of small thoracic fishes, of a mucilaginous skin, which the Indians designate by the name of popoyote or axolotl*, although the true axolotl of the lakes of Mexico (Siren pis ciformis of Shaw) differs essentially from it, and is only according to M. Cuvier, the larva of a great salamander. These fishes, which by rotting in heaps diffuse emanations through the neighbouring air, are justly considered the principal cause of the putrid bilious fevers which prevail on that coast. Between the town and the cienega, there are lime fur

*The axolotl of Acapulco has nothing in common with that of the valley of Mexico, but its colour. It is a scaly fish with two dorsal fins, of an olive brown, speckled with small yellow and blue spots.