A sexually transmitted disease is an illness that has a significant probability of transmission between humans or animals by means of sexual contact, including vaginal intercourse, oral sex, and anal sex.

Syphilis is a sexually transmitted disease caused by the spirochetal bacterium Treponema pallidum subspecies pallidum. Transmission of syphilis is always through sexual contact, although there are examples of congenital syphilis via transmission from mother to child in utero.

Syphilis is a still more terrible venereal disease. It usually appears first in small, hard sores, hard chancres, on the sexual parts or the mouth. Then the syphilitic poison spreads throughout the whole body by means of the blood. After a few weeks it breaks out on the face or body. Its final cure is always questionable. Syphilis may lie dormant for years, and then suddenly become active again. It breaks out in sores on all parts of the body, often eats up the bone, destroys internal organs, such as the liver, causes hardening of the lungs, diseases of the blood vessels and eye diseases. Ulcers of the brain and nerve paralysis often result from it.

One of its most terrible consequences is consumption of the spinal marrow and paralysis of the brain, or paresis. The first slowly hardens and destroys the spinal marrow, the second the brain. These diseases are only developed by previous syphilitics. As a rule they occur from 5 to 20 years after infection, usually 10 or 15 years after it. And they usually happen to persons who believed themselves completely cured. Consumption of the spinal marrow leads to death in the course of a few years of continual torture. Paralysis of the brain turns the sufferer into a human ruin, gradually extinguishing all mental and nervous functions, sentience, movement, speech and intellect.

One danger of syphilis is the fact that its true nature may be overlooked during the first period, because of the lack of pronounced symptoms. Its early sores may easily be mistaken for some skin affection. Mercury and other means are successful in doing away with at least the more noticeable signs of syphilis during the first and secondary stages. The modern medical treatment using mercury and Salvarsan (606) in alternation, has been very successful.

It is claimed that by following it, syphilis may be totally cured if taken in hand during the first stage. The sores developed during the first two or three years of the disease are very infectious. In the case of a chronic syphilis of three or four years' standing, the sores as a rule are no longer infectious.

It is possible, however, for a syphilitic of this description to bring forth syphilitic children, without infecting his wife. Such children either die at birth, or later, of this congenital syphilis. They may also die of spinal consumption or paresis between the ages of 10 and 20.

The mortality of all syphilitic children is very great. In most cases, however, healthy children are born of the wedlock of relatively cured syphilitics, though they are often sterile. Young men who have had recourse to prostitutes, often inoculate their wives with gonorrhea or syphilis, and thus the plague is spread.