1. Cynomolgus monkeys were subjected to a series of non-traumatic exposures of the mucous membranes of the alimentary tract, designed to test the relative permeability to poliomyelitis virus of its upper and lower portions.
2. In the first stage, dried poliomyelitis virus of tested potency was administered in fat-covered capsules to 26 monkeys in such a way as to avoid contamination of the oropharynx but to permit thorough exposure of the gastro-intestinal mucosae. No clinical evidence of poliomyelitic infection appeared.
3. Subsequent application of small amounts of virus to the tongues of 18 of the same monkeys caused paralytic poliomyelitis in one of them.
4. Virus given subsequently by enema to 11 of the monkeys caused no clinical manifestations of poliomyelitis.
5. Of 7 monkeys later treated with virus by oronasal spraying, one developed typical preparalytic signs of infection, and the distribution of lesions indicated that entry had occurred through the afferent nerves of the oropharynx and, possibly, the esophagus.
6. The 6 surviving monkeys were exposed to virus by inhalation. One of them developed paralytic poliomyelitis by olfactory entry. The others appeared to have acquired some resistance to infection.
7. The 5 surviving monkeys were inoculated intracerebrally, as a test of immunity. One of them developed paralytic poliomyelitis. The other 4 showed no clinical signs of infection, but all had typical lesions of varying extent and intensity in the central nervous system.
8. A histological examination of the peripheral nervous ganglia in 12 of the exposed monkeys sacrificed at various stages of the experiments revealed lesions compatible with poliomyelitis in all. Ganglia connected with the head alone (Gasserian, cervical sympathetic) were more constantly and, on the average, more severely involved than the celiac, which is connected only with the intestine.
9. While the celiac ganglion was involved in 7 cases, no evidence was found of the spread of infection from it to the spinal cord.