INFANTILE PARALYSIS.—See PARALYSIS.
INFECTION.—The exciting causes of contagious diseases are either transmitted directly by the patient, his immediate surroundings, or his excreta ; or they are distributed over large areas by the medium of the air. Infection through the air is possible with the readily transportable germs of influenza, measles, smallpox, scarlet fever, whooping-cough, mumps, etc. Where the germs are communicated directly from one individual to another (as in typhoid fever, diphtheria, cholera, tuberculosis, hydrophobia, venereal diseases, etc.), the contagion occurs through the medium of the clothes or various personal utensils, or through insufficient cleansing of the hands before eating, especially when they have been in contact with the sick person or with anything belonging to him. Infection may result also from the ingestion of food materials containing disease-germs, especially water and raw milk ; from bathing in streams which are contaminated by the drainage from infected localities ; or from using unclean water for washing eating utensils. Bacteria may be transmitted also by insects, particularly through their bites (malaria ; yellow fever), or by their contaminating food or open wounds after having been in contact with infectious materials ; typhoid, for instance, is often transmitted in this manner by flies.
The spread of contagious diseases is furthered by lax health-laws, by incorrect methods of living, by inadequate drainage, by lack of pure and wholesome drinking-water, by damp and over-crowded dwellings which lack a sufficient amount of light and air, by insufficient attention to the cleanliness of the body and surroundings, and by neglected or incomplete isolation of patients suffering from contagious diseases. The risk of infection is increased also by the mode of living necessitated by certain callings, and by the diminished resistance of the body resulting from such occupations. Other exciting factors are : severe exertions, sudden changes in temperature, prolonged detention in dry, hot, or cold air, working in the water, the development of dangerous gases or moisture, abuse of alcohol or other toxic substances, etc., etc.
Measures for preventing contagious diseases, or their spread in any given case, had best be prescribed by a physician who is familiar with the subject and its dangerous aspects. It is essential, therefore, to summon medical aid at once in every suspicious case, so that the patient may be placed under appropriate treatment, and further evil consequences avoided. In cases where disease has been transmitted through the air, the patient should at once be isolated and, if necessary, placed in a hospital. If the patient be a member of a large family, the remaining members, as %veil as the servants, should not be permitted to come in contact with the patient's nurse, nor to have any communication with her, as many diseases, such as scarlet fever and smallpox, may be readily transmitted through an intermediary. Nurses must observe extreme cleanliness of their persons. They should rinse the mouth frequently, bathe the entire body every day, change their under clothing oftener than usual, and wear protective gowns made from washable material. Above all, they must not take their meals in the sick-room. The disinfection of the patient's excreta. clothing, and utensils is fully treated in the article on DISINFECTION. The sick-room should always be well aired ; it should be thoroughly disinfected after the illness, and, if possible, not occu pied until several weeks later.
During the prevalence of an epidemic the appearance of bronchial, gastric, or intestinal catarrhs should be given special attention, because the inflammatory condition present in these cases greatly favours the entrance of germs and their transmission through the body. All over-indulgence in eating and drinking must be strictly avoided, and a perfectly normal mode of living insisted upon.