Because the route of infection of many of the pathogenic bacteria and filtrable viruses is by way of the upper respiratory tract, biotherapy and chemotherapy in the prevention and treatment of the local and systemic diseases they produce are of particular interest and importance to otolaryngologists, especially those practicing in the temperate and colder climates, where droplet infections are of frequent occurrence. It is true that many of the infectious diseases of the ears, nose and throat remain localized, but not infrequently they involve by extension the lower respiratory tract with production of bronchitis, pneumonia and bronchiectasis, the meninges with production of severe and highly fatal types of suppurative meningitis, and the blood with production of septicemia. Furthermore, chronic localized areas of infection, especially those in the nasal accessory sinuses and tonsils, are frequently important in relation to the etiology of the diseases due to focal infection.
PROPHYLACTIC VACCINATION
Pertussis.—There