Among the most important unsolved problems in infantile paralysis is the port of entry of the virus. The recent experimental work of Howe and Bodian, supported by the Commonwealth Fund and reported in the August issue of the Bulletin of the Johns Hopkins Hospital, presents an opportunity for reviewing some of the newer facts and concepts with regard to the nature of this disease.
In estimating the rate of progression of poliomyelitis virus in the sciatic nerve of the rhesus monkey,1 the investigators inoculated the nerve at a single point and subsequently cut it at a higher level, at various intervals in different animals, to prevent an infective dose of virus from reaching the spinal cord. The rate was estimated to be approximately 2.4 mm. an hour. An attempt was made thus to control the variability introduced by the incubation period. The method of inoculation, the homogeneity of the