The manner of conveyance of the virus of poliomyelitis to infected persons is not yet wholly worked out. The presence of the virus has been established on the mucous membrane of the nose, throat and intestines of persons ill of poliomyelitis, and on the mucous membrane of the nose and throat of monkeys in which the disease has been produced experimentally. Aside from infected persons and monkeys the virus has once been found in external nature; namely, in sweepings obtained from a room in which patients with poliomyelitis had recently been kept (Neustaedter and Thro). The latter finding indicates that the virus is capable of leaving the infected body in a manner that permits of its persistence as dust. Since the virus has been shown to occur frequently, if not constantly, in the discharges of the nose and throat, it is clear that it must escape into the surroundings of