The antitoxin produced in the contest of the body cells against some diseases will not only neutralise the toxin of a particular disease, but it will also neutralise the toxin of a second disease. By vaccinating a person we inoculate him with vaccinia or cowpox. His body cells make an antitoxin which neutralises the toxin or virus of cowpox, he recovers from this light disease, and the antitoxin now remaining in his body prevents for years another successful inoculation with cowpox. It does more: in 90 per centum of cases it will prevent successful infection with smallpox.
Smallpox (the pocks, pokes or pockets of matter,—opposed to the great pox or syphilis) has been known from very early times—probably even from 1200 B.C. The name "small pokkes" was first used in England in 1518. The disease was brought to America in 1507.
It may be communicated from the sick to the healthy (1) by persons suffering with the disease; (2) by bodies of persons that have died of smallpox; (3) by infected articles; (4) by healthy third persons; (5) by the air, to persons living even at some distance; (6) by inoculation. The poison enters the body by the mucous membrane of the nose, mouth, or respiratory tract, and probably through the mucous membrane of the stomach and through the broken skin.
Patients can communicate the disease probably during the period of incubation (from 5 to 20 days after exposure to the disease—commonly about 14 days); and certainly from the initial stage until no trace is left of the final skin-desquamation. The infection is most active during the formation and duration of the pocks. The mildest smallpox in one person can cause malignant smallpox in another, and vice versa. The mortality in the unvaccinated is between 40 and 50 per centum.
A typical case of confluent smallpox at its height is the [{173}] ugliest disease in appearance and stench and almost in substance, known to medicine. Anyone liable to infection by it, or likely to carry it to others, who says he is "not afraid of it," has either never seen it and he is talking childish nonsense, or he has seen it and he is a fool.
The face is a bloated mass of corruption; the eyes are swollen shut; the nose, cheeks, lips, and neck are puffed out enormously; the mouth is a large sore, ulcerous, and spittle trickles from it ceaselessly. The fever is up to 103 or 105 degrees; there is an unquenchable thirst, a vile stench, sleeplessness; often delirium is the only relief, and there is one chance in two of a disfigured recovery. Tobacco, alcoholic liquor and a walk in the fresh air will not disinfect the visitor to such a disease. Years ago I investigated in the laboratory the popular notion that tobacco is a disinfectant. I found that bacteria, the diphtheria bacillus and swarms of others more delicate, will grow as well in the presence of a large piece of "Navy Plug," as when tobacco is absent. Chewing tobacco, whiskey, a walk in the fresh air as disinfectants, the Sioux medicine-man's powwow, the hind leg of a rabbit as a charm, are all in the same category.
The first and chief protection against smallpox is vaccination. Vaccination does not always prevent infection by smallpox, but it does prevent it in more than 90 per centum of exposures to the disease. Welch reported in 1894 that the death-rate in one series of 5,000 cases of smallpox was 58 per centum in the unvaccinated, and 16 per centum in the vaccinated, but the vaccinated took the disease in less than 10 per centum of the exposures. During the Franco-German War in 1870-1871, the Germans who had a million vaccinated men lost 458 soldiers from smallpox while a great epidemic of smallpox was existing in Germany; the French, who were indifferent to vaccination, during the same time lost 23,400 men from this disease alone. In the United States, where there is no compulsory vaccination except such attempts as school boards make, there were between July and December, 1903, 13,739 cases of smallpox; in Germany, where there is a compulsory [{174}] vaccination law, there was no smallpox at all, during the same time, except 14 cases in two seaports, Bremen and Kiel, whither the infection had been brought from without.
Before 1874 there had been no compulsory vaccination law in Germany except for the army. In 1871, 143,000 Germans died of smallpox. Since the law went into effect in 1874 the disease has been stamped out, until there was between July and December, 1903, only one death from smallpox in Germany.
The chart on page 175 will show very graphically the effect of vaccination upon smallpox.
In October, 1898, smallpox was endemic in Puerto Rico; in December, 1898, it was epidemic; in January, 1899, it was all over the island and spreading rapidly. In February, 1899, compulsory vaccination was begun and carried out for only four months, when 860,000 vaccinations had been made in a population of about 960,000 people. The death-rate from smallpox dropped from 621 a year to 2.