the last-mentioned country it was reported, in 1897, that there were 23,647 lepers, a majority of whom were located in the coast region of the islands. In 1893 the total number of lepers in Egypt was 2204. In Spain, Portugal, France, and Italy a limited number of cases of leprosy may be found, but Great Britain Holland, Belgium, Germany, Austria, Switzerland, and Denmark are practically free from the disease— a few imported cases no doubt exist in each of these countries. In Norway, which for many years has been the principal infected centre in Europe, the number of cases has been constantly diminishing during the past fifty years. In 1856 the number of cases reported was 2870, in 1895 the number had fallen to 688. The reduction was partly due to the emigration of lepers to other countries (287). In Russia 1200 cases of leprosy were reported as living within the limits of the empire in the year 1895, when an official census was taken.

In South America and in the West Indies there are a considerable number of lepers, especially along the coast of Brazil and of British Guiana. The disease also exists in the states of Central America and in Mexico.

Cases of leprosy not infrequently arrive in the United States from Norway, from China, or from the Hawaiian Islands, but the policy of the Govern

ment and State health authorities now is to return them to their native countries when practicable.

We have in the United States one centre of leprosy infection which has existed for many years, and in which new cases are still developed from time to time. This is in Louisiana. According to Dr. Dyer, who has made a special investigation with reference to leprosy in New Orleans and vicinity, 270 cases have developed in that State since 1878. Of these, 171 were born in Louisiana and 39 were born in Europe.

What has already been said with reference to the history and geographical distribution of leprosy indicates that even when no special precautions are taken there is little danger that the disease will spread to any extent in countries where the people are accustomed to civilised ways of living and pay a reasonable degree of attention to cleanliness. Nevertheless, most writers upon the subject, and health authorities, national and local, insist upon the isolation of lepers; and, where there are a considerable number of these unfortunates, upon their segregation in suitably located colonies, where they can have whatever comfort and enjoyment is possible under the conditions existing in such isolated localities, while at the same time they are removed from the possibility of communicating the disease to others. I am in full accord with

this policy. But the unreasonable fear of lepers, which has existed from the earliest times, and is often manifested at the present day, is evidently not justified, in view of the very remote danger of the disease being contracted by any ordinary association with them. The danger from tuberculosis is far greater, and this disease claims nearly 150,000 victims annually within the limits of the United States, yet no one proposes the isolation of cases of pulmonary tuberculosis, and indeed this is not necessary for the prevention of the disease if the complete disinfection of all infectious material can be secured—that is, of the material expectorated by those suffering from the disease. In leprosy it will, of course, be advisable to destroy all pus, saliva, etc., which contains the bacillus, but we can scarcely insist upon the rigid measures of disinfection which are essential for the prevention of diphtheria, or smallpox, in view of the fact that painstaking researches fail to show that the disease, under ordinary conditions as they exist to-day, is communicated to healthy individuals who are associated in an intimate way with the sick.

CHAPTER IX

DIPHTHERIA

IPHTHERIA, like tuberculosis, is a disease

which is propagated principally through the medium of the sputa of infected individuals, which contains in large numbers the specific bacillus to which the disease is due. This bacillus effects a lodgment in the fauces, or in the posterior nasal passages of susceptible individuals and invades the mucous membrane, causing a localised inflammation and a fibrinous exudation — so-called "false membrane." Its first appearance is very commonly upon the tonsils. As the disease progresses symptoms of poisoning by the deadly toxin of the diphtheria bacillus are developed.

The disease is more frequent and more fatal in young children than in adults. The mortality is greatest in infants and comparatively low in children. over twelve years of age. The disease differs greatly as to its malignancy during different epidemics.

There are evidently many different breeds of the diphtheria bacillus, and its pathogenic virulence is increased or diminished as a result of conditions relating to its growth. A series of cases in very susceptible individuals is favourable to an increase in the virulence of the germ. On the other hand, when obtained from the throat of one who is comparatively immune, or cultivated in artificial media outside of the body, it is less virulent.

While the most robust children are subject to attack, delicate and poorly nourished children are more susceptible and more likely to die. A chronic or acute catarrhal inflammation of the throat or nasal passages predisposes to infection.

The bacillus of diphtheria was first described by the German pathologist, Klebs, in 1883, and the following year the fact that it is the specific cause of this disease was demonstrated by Löffler, a surgeon in the German army and a pioneer in bacteriological researches. Hence it is often spoken of as "the Klebs-Löffler bacillus." Cultures of this bacillus are very pathogenic for guinea-pigs, rabbits, chickens, pigeons, and cats, and to a less extent for dogs, horses, and cattle. Rats and mice have a natural immunity. The immunity of certain individuals is shown by the fact that when associated with diphtheria patients they may carry virulent diphtheria