There did not appear to be any advantage from smelling vinegar, tar, camphor, or volatile salts, in preventing the disease. Bark and wine were equally ineffectual for that purpose. I was called to many hundred people who were infected after using one or more of them. Nor did the white washing of walls secure families from the disease. I am disposed to believe garlic was the only substance that was in any degree useful in preventing it. I met with several persons who chewed it constantly, and who were much exposed to the miasmata, without being infected. All other substances seemed to do harm by begetting a false confidence in the mind, to the exclusion of more rational preservatives. I have suspected further, that such of them as were of a volatile nature helped to spread the disease by affording a vehicle for miasmata through the air.
There was great mortality in all those families who lived in wooden houses. Whether this arose from the small size of these houses, or from the want of cleanliness of the people who occupied them, or from the miasmata becoming more accumulated, by adhering to the wood, I am unable to determine. Perhaps it was the effect of the co-operation of all three of those causes.
I have said, formerly, that intemperance in drinking predisposed to the disease; but there were several instances of persons having escaped it who were constantly under the influence of strong drink. The stimulus of ardent spirits probably predominated over the stimulus of the miasmata, and thus excited an artificial fever which defended the system from that which was epidemic.
I heard of some sea-faring people who lived on board their vessels who escaped the disease. The smell of the tar was supposed to have preserved them; but, from its being ineffectual in other cases, I am disposed to ascribe their escape to the infected air of the city being destroyed by a mixture with the water of the Delaware.
Many people who were infected in the city were attacked by the disease in the country, but they did not propagate it, even to persons who slept in the same room with them.
Dr. Lind informs us that many persons escaped the yellow fever which prevailed in Pensacola in the year 1765, by retiring to the ships which lay in the harbour, and that when the disease had been taken, the pure air of the water changed it into an intermitting fever[47]. The same changes have frequently been produced in malignant fevers, by sending patients infected with them from the foul air of a city, into the pure air of the country.
Persons confined in the house of employment, in the hospital, and in the jail, escaped the fever. The airy and remote situation of those buildings was probably the chief means of their preservation. Perhaps they derived additional security from their simple diet, their exemption from hard labour, and from being constantly sheltered from heat and cold.
Several families, who shut up their front and back doors and windows, and avoided going out of their houses except to procure provisions, escaped the disease.
I have taken some pains to ascertain, whether any class of tradesmen escaped the fever, or whether there was any species of labour which protected from it. The result of my inquiries is as follows: Three butchers only, out of nearly one hundred who remained in the city, died with the disease. Many of them attended the markets every day. Two painters, who worked at their business during the whole time of the prevalence of the fever, and in exposed situations, escaped it. Out of forty scavengers who were employed in collecting and carrying away the dirt of the streets, only one was affected by the fever and died. Very few grave-diggers, compared with the number who were employed in that business, were infected; and it is well known, that scarcely an instance was heard of persons taking the disease, who were constantly employed in digging cellars. The fact is not new that grave-diggers escape malignant fevers. It is taken notice of by Dr. Clark.