The ways in which diphtheria bacilli may be conveyed from sick to healthy persons are almost countless. In ordinary breathing the ex pired breath contains no germs, but in speaking and especially in coughing, a fine spray is emit, ted which may contain the bacilli and.thus convey the disease.. All sorts of articles, such as handkerchiefs, toys, drinking uteusils, fund. ture, clothing, bed-linen and the like, may be come contaminated with the bacilli and be the means of spreading the disease. The specific germs have been found in the hair, on the shoes, and elsewhere on the persons of those brought into frequent and close proximity to the patient. Direct contact with the patient, as in kissing, may communicate the disease. It is especially through direct or mediate contact with in fected individuals that the disease is spread. Hence, preventive measures, consisting in iso lation of the patient till the bacilli have dis appeared from the throat, and in thorough dis infection, are of the first importance in checking the spread of diphtheria. Insanitary conditions, formerly thought to be the direct cause of diph theria, are now regarded only as accessory causes in affording opportunities for the pro longed survival of the specific germs or in weakening the powers of resistance of the in dividual.
The discovery of the diphtheria bacillus has led to the introduction of a new and most successful method of treatment of the disease, known as serum-therapy or the antitoxin treat ment. The establishment of the principles and the introduction of this treatment are due espe cially to Behring of Germany and Roux in Pans. The underlying principle of the treat ment is based on the fact that, if a susceptible animal is inoculated first with small and then with increasing doses of the toxin produced by the bacillus, the blood of the animal is found to contain a substance called antitoxin, which has the power of neutralizing or rendering harmless the toxin. In order to obtain large
quantities of the healing serum a horse is gen erally selected for the process of immunization. By proper methods very powerful antitoxins can be obtained. The antitoxin is used not only to cure the disease, but also to render persons insusceptible for a time to the disease. This latter procedure of preventive inoculation has been found especially useful in preventing ex tensive outbreaks in children's hospitals and asy lums after the introduction of one or more cases of diphtheria. Dr. William H. Welch, of the Johns Hopkins University, in 1895, in an analysis of over 7,000 cases of diphtheria treated by anti toxin found that the fatality was reduced by this treatment by over 50 per cent of the previous death-rates; he concluded that the antitoxin serum is a specific curative agent for diphtheria, surpassing in its efficacy all other known meth ods of treatment for this disease. Since his re port, this conclusion has been confirmed and even more favorable results have been obtained.
Some idea of the great benefits which have been derived from the discoveries outlined above may be had by comparing the death rate before and after the serum therapy became the prac tice. For the five years immediately preceding the discovery and use of antitoxin in the city of Berlin the death rate for diphtheria in every 10,000 inhabitants was 102 per cent, and for the next five years it fell to 3.7 per cent; in Paris, 6.5 per oent before antitoxin, and 1.3 per cent afterward; in New York 14.5 per cent be fore, and 6.3 per cent after antitoxin. So safe is the use of antitoxin, it is now advised that every child exposed should receive an immuniz ing dose, as that confers protection.