Answer:
Because people did not know that yellow fever was caused by the bite of an infected mosquito, they assumed incorrectly that people could catch the disease through touch. To help control the disease, letters were cleaned with vinegar before being sent. This did not work, because it was a false cause-and-effect relationship.
<span>.<span>Pathos is an appeal to emotion, and is a way of convincing an audience of an argument by creating an emotional response.</span></span>