tended with success”, although this bark has frequently produced the most salutary effect in the West India Islands, and in Spain. # It is possible that this difference of action arises from the variety of forms assumed by the disease, according as the remission is more or less marked, or as the gastric symptoms predominate over the adynamical symptoms. Mercurial preparations, especially calomel or muriate of sweet mercury with jalap, have frequently been employed at Vera Cruz; but these remedies, so much boasted at Philadelphia and Jamaica, and prescribed in ataxical fevers by the Spanish physicians of the sixteenth century f, have been very generally abandoned by the Mexican physicians. They have been more fortunate in the use of frictions of oil of olives, the utility of which was acknowledged by M. Ximenez of the Havanah, by Don Juan de Arias of Carthagena, de las Indias", and especially by my friend M. Keutsch, a distinguished physician of the island of Santa Cruz, who has collected many interesting observations respecting the yellow fever of the West India Islands. For some time sherbets, the juice of ananas (rugo de piña) and the influence of the palo mulato, a vegetable of the amyris genus, were considered at Vera Cruz as specifics against the vomito ; but a long and melancholy experience has gradually discredited these medicines even among the lower order of Mexicans. If they are to be reckoned among the best prophylactic means, they cannot however be the basis of a curative treatment. As an excessive heat increases the action of the bilious system, the use of ice must be very salutary under the torrid zone. Relays have been!established for the purpose of carrying the snow with the greatest celerity on mules, from the slope of the volcanos of Orizaba to the port of Vera Cruz. The length of road which the snow post (posta de nieve) travels is twentyeight leagues. The Indians make choice of pieces of snow mixed with agglutinated hail. According to an antient custom, they wrap up these masses with dried herbs, and sometimes even with ashes, two substances which we know to be bad conductors of caloric. Although the mules loaded with the snow of Orizaba arrive in full trot at Vera Cruz, more than the half of the snow is nevertheless melted during the road, the temperature of the atmosphere being constantly, in summer, from 29 to 80 degrees of the centigrade thermometer. * Notwithstanding these obstacles, the inhabitants of the coast may daily procure sherbets of ice water. This advantage, which is not possessed in the West India Islands, at Carthagena, and Panama, is of the greatest consequence to a town which is daily frequented by men born in Europe, and on the central table land of New Spain. Although the yellow fever is not dangerous by immediate contact at Vera Cruz, and it is in no wise probable that it ever was introduced there from any other place t, it is not the less certain that it only appears at certain periods, without any discovery having yet been made of the modifications of atmosphere which under

the torrid zone produce these periodical changes. It is to be regretted that the history of the epidemics does not go farther back than half a century. The great military hospital of Vera Cruz was established in December 1764, but in no document preserved in the archives of that hospital is any mention made of the diseases which preceded the vomito of 1762. This epidemic, which began under the viceroyship of the Marquis de Croix continued its ravages till 1775, when, after paving the streets of Vera Cruz, they made some feeble attempts to diminish the extreme dirtiness of the town. The inhabitants at first imagined that the pavement would increase the insalubrity of the air by augmenting, from the reverberation of the solar rays, the insupportable heat which prevails within the town; but when they saw that the vomito did not make its appearance . from 1776 to 1794, they then believed that this pavement had secured them for ever from it, without reflecting that the marshes of stagnant water situated to the south and east of the town, continued to pour into the atmosphere the putrid emanations which in all times were regarded at Vera Cruz as the principal focus of the deleterious miasmata. It is a very remarkable fact, that during the eight years which preceded 1794, there was not a single example of vomito, although the concourse of WOL. IV, O

Europeans and Mexicans from the interior was extremely great, and the sailors not seasoned to the climate, gave themselves up to the same excesses which are now laid to their charge, and although the town was not so clean as it has been since the year 1800.

2. The cruel epidemic which appeared in 1794, began with the arrival of three vessels of war, the ship El Mino, the frigate Venus, and the howker Santa Vibiana, which had all touched at Porto Rico. As these vessels contained a great number of young sailors not seasoned to the climate, the vomito commenced then at Vera Cruz with extreme violence. Between 1794 and 1804, the disease re-appeared every year when the north winds ceased to blow. We see that between 1787 and 1794, the royal military hospital” only received 16,835 patients,

*This hospital receives all patients who come by sea. There were,

Years. Treated. | Died.

w

In 1792 2887 71
1793 2907 77
1794 4195 453
1795 3596 42]
1796 3181 176
1797 4727 478
1798 5186 195
1799 || 14672 891
1800 9294 505
1801 7120 226
1802 5242 44l