DIFFUSION AND SURVIVAL OF THE POLIOMYELITIC VIRUS.

The ordinary virus of poliomyelitis present in aseptically removed brain tissue of paralyzed monkeys survives in an ascitic fluid kidney medium at the temperature of 37 degrees C. for a period of at least twenty, but not of thirty days. Under the conditions of moderate anaerobiosis, the minute microorganism cultivated from poliomyelitic tissues tends not to develop in cultures from the brain tissue; hence its presence does not complicate the survival test. The diffusion of the ordinary poliomyelitic virus from a noncomminuted fragment of brain tissue into a surrounding medium of ascitic fluid is so slight as not to be detectable by inoculation experiments conducted with usual quantities of the fluid. The specific effects of the microörganism cultivated from poliomyelitic tissues are not caused by an admixture in the cultures of the ordinary virus of poliomyelitis; hence they must be caused by the pathogenic action of the microörganism itself. The minute microörganism is therefore to be regarded as the specific microbic cause of epidemic poliomyelitis.