It is no objection to the inference which follows from these facts, that the common remitting fever was not known during the above period in the neighbourhood of this city, and in many other parts of the state, where it had usually appeared in the autumnal months. There is a certain combination of moisture with heat, which is essential to the production of the remote cause of a bilious fever. Where the heat is so intense, or of such long duration, as wholly to dissipate moisture, or when the rains are so great as totally to overflow the marshy ground, or to wash away putrid masses of matter, no fever can be produced. Dr. Dazilles, in his treatise upon the diseases of the negroes in the West-Indies, informs us, that the _rainy_ season is the most healthy at Cayenne, owing to the neighbouring morasses being _deeply_ overflowed; whereas, at St. Domingo, a _dry_ season is most productive of diseases, owing to its favouring those degrees of moisture which produce morbid exhalations. These facts will explain the reason why, in certain seasons, places which are naturally healthy in our country become sickly, while those places which are naturally sickly escape the prevailing epidemic. Previously to the dissipation of the moisture from the putrid masses of vegetable matters in our streets, and in the neighbourhood of the city, there were (as several practitioners can testify) many cases of mild remittents, but they all disappeared about the first week in September. It is worthy of notice, that the yellow fever prevailed in Virginia in the year 1741, and in Charleston, in South-Carolina, in the year 1699, in both which years it prevailed in Philadelphia. Its prevalence in Charleston is taken notice of in a letter, dated November 18th, O. S. 1699, from Isaac Norris to one of his correspondents. The letter says, that "150 persons had died in Charleston in a few days," that "the survivors fled into the country," and that "the town was thinned to a very few people." Is it not probable, from the prevalence of this fever twice in two places in the same years, that it was produced (as in 1793) by a general constitution of air, co-operating with miasmata, which favoured its generation in different parts of the continent? But again, such was the state of the air in the summer of 1793, that it predisposed other animals to diseases, besides the human species. In some parts of New-Jersey, a disease prevailed with great mortality among the horses, and in Virginia among the cows, during the autumn. The urine in both was yellow.--Large abscesses appeared in different parts of the body in the latter animals, which, when opened, discharged a yellow serous fluid. From the colour of these discharges, and of the urine, the disease got the name of the _yellow water_.