This good news was followed almost immediately by a contradic­tory report from Comptroller Wolcott. After several good days in the city, he explained, warm weather reappeared and deaths increased, jumping to 82 on October 22. Wolcott advised the president to delay his return trip several more days. . . . This didn't please the anxious president, who had already been out of touch with critically important matters for over six weeks. He could write back and ask again what was happening in the city, but this would take an unbearable amount of time. Before the fever, a letter could travel by fast post from his home to the city and a reply be received in three to six days. Now letters to and from Philadelphia had to undergo special processing, such as being dipped in vinegar and allowed to dry. It was taking mail anywhere from ten days to two weeks to make the journey these days! Further delay was out of the question.

—An American Plague,
Jim Murphy

Based on the passage and what you have learned in the lesson, write three to four sentences explaining whether dipping letters in vinegar to prevent the spread of yellow fever was a good conclusion.