Syphilis. Approximately two years after Columbus reached the New World, an unknown disease appeared among the ranks of a French army that was laying siege to the southern Italian city of Naples. Characterized by terrible pain, swelling, and open sores on the penis and scrotum, the disease was recognized by the surgeons and physicians who treated it as a new kind of venereal disease. Unlike gonorrhea, this new disease led to secondary skin lesions on almost any part of the body, along with skeletal pains that made sleep difficult. The French army blamed it on the locals, calling it the Neapolitan Disease. Much of the rest of Europe associated it with the invading French, whose army disbanded in 1495, further spreading it, and called it the French Disease, or simply the pox. It became known as syphilis, a name first used...