With a method of intranasal instillation of poliomyelitis virus that brings about infection of all M. rhesus monkeys subjected to it, a study was undertaken of the fate of nasally instilled virus in normal and convalescent, immune animals. Control experiments revealed that nasal mucosa of normal monkeys contained no observable antiviral factors and that when five or ten minimal cerebral infective doses were added to the mucosa, virus could be detected by the employed procedure. In the olfactory bulbs even a single infective dose could be recovered, since suspensions of both bulbs could be transferred to the brain of a monkey without any loss of material.
After nasal instillation of virus in normal monkeys, it disappeared quickly (4 hours or less) and could be recovered neither from the excised nasal mucosa nor from the olfactory bulbs during the first 48 hours. At 72 hours, just before or coincident with the first rise of temperature, virus was found in very small amounts in the nasal mucosa and for the first time also in the olfactory bulbs. At 96 hours, at least 3 days before the appearance of nervous signs, and later, while virus continued to be present in considerable amounts in the olfactory bulbs (and presumably elsewhere in the central nervous system), none was detected in the nasal mucosa. In convalescent, immune animals receiving the same strain of virus intranasally which caused the original infection, none could be recovered from the nasal mucosa or central nervous system at 4 hours, 1, 2, 3, 4, 5, and 7 days. The bearing of these observations on the problem of host to host transmission of poliomyelitis virus is discussed.