In all of them the stomach was inflamed. The matter which constitutes what is called the _black vomit_, was found in the stomachs of several patients who had not discharged it at any time by vomiting. In some stomachs, he found lines which seemed to separate the living from their dead parts. Those parts, though dead, were not always in a mortified state. They were distinguished from the living parts by a peculiar paleness, and by discovering a weak texture upon being pressed between the fingers. He observed the greatest marks of inflammation in the stomachs of several persons in whom there had been no vomiting, during the whole course of the disease. The brain, in a few instances, discovered marks of inflammation. Water was now and then found in its ventricles, but always of its natural colour, even in those persons whose skins were yellow. The liver suffered but little in this disease. It may serve to increase our knowledge of the influence of local circumstances upon epidemics to remark, that this viscus, which was rarely diseased in the fever of Philadelphia in 1798, discovered marks of great inflammation in the bodies which were examined by Dr. Rand and Dr. Warren, in the town of Boston, where the yellow fever prevailed at the same time it did in Philadelphia. The weather was hot and dry in August and September, during the prevalence of this fever. Its influence upon animal and vegetable life are worthy of notice. Moschetoes abounded, as usual in sickly seasons; grasshoppers covered the ground in many places; cabbages and other garden vegetables, and even fields of clover, were devoured by them. Peaches ripened this year three weeks sooner than in ordinary summers, and apples rotted much sooner than usual after being gathered in the autumn. Many fruit-trees blossomed in October, and a second crop of small apples and cherries were seen in November, on the west side of Schuylkill, near the city. Meteors were observed in several places. On the 29th of September there was a white frost. Its effects upon the fever were obvious and general. It declined, in every part of the city, to such a degree as to induce many people to return from the country. In the beginning of October the weather again became warm, and the disease revived. It was observable, that all great changes in the weather from heat to cold that were short of frost, or of cold to heat, increased the mortality of the fever. It spread most rapidly in moist weather. The origin of this fever was from the exhalations of gutters, docks, cellars, common sewers, ponds of stagnating water, and from the foul air of the ship formerly mentioned. The fever prevailed at the same time in the town of Chester, in Pennsylvania; in Wilmington, in the state of Delaware; in New-York; in New-London, in Connecticut; in Windsor, in Vermont; and in Boston; in all which places its origin was traced to domestic sources.