That the plague was not what is commonly called contagious, like the scarlet fever, or extinct smallpox, was proved. It was called an epidemic. But the grand question was still unsettled of how this epidemic was generated and increased. If infection depended upon the air, the air was subject to infection. As for instance, a typhus fever has been brought by ships to one seaport town; yet the very people who brought it there, were incapable of communicating it in a town more fortunately situated. But how are we to judge of airs, and pronounce⁠—in such a city plague will die unproductive; in such another, nature has provided for it a plentiful harvest? In the same way, individuals may escape ninety-nine times, and receive the deathblow at the hundredth; because bodies are sometimes in a state to reject the infection of malady, and at others, thirsty to imbibe it. These reflections made our legislators pause, before they could decide on the laws to be put in force. The evil was so wide-spreading, so violent and immedicable, that no care, no prevention could be judged superfluous, which even added a chance to our escape.