Experiments on the Cultivation of the Virus of Poliomyelitis

It has not hitherto been found possible to cultivate the virus, or etiologic cause, of epidemic poliomyelitis outside the animal body. Flexner and Lewis1noted that when a Berkefeld filtrate, prepared from the infected nervous system of the monkey, was mixed with ascitic fluid and the mixture incubated a turbidity arose; but they could not determine that the turbidity was caused by multiplication of a living microorganism. Only the original mixture, and not the subcultures, was capable of infecting monkeys. Recently the efforts at cultivation of the virus have been resumed. Encouraged by the cultivation of the spirochetes by Noguchi we concluded to apply the methods worked out by him2to the investigation of poliomyelitis. Since the results achieved so far are of quite a different order from those obtained previously, we shall describe them briefly here. The virus belongs to the class of filterable organisms and passes