Olfactory Tract and Poliomyelitis. ∗

Abstract

Faber 1 has recently reviewed clinical and experimental evidence in support of the view that acute poliomyelitis is primarily a disease of the central nervous system. It is well established that virus deposited on the nasal mucous membranes in some way gains admission to the central nervous system. We have described 2 a method which has enabled us to infect 95% of monkeys inoculated with virus by the intranasal route. While it may be assumed from the evidence already reported that the virus gains entrance to the central nervous system by the way of the olfactory nerve no satisfactory proof that this is the normal route has thus far been produced. The observations we desire to report seem to offer this final evidence. This rests on a failure to infect monkeys by the intranasal route after the olfactory tracts have been sectioned with an electric cautery.

Six Macacus rhesus monkeys were subjected (12/6/33) to the following operation while under deep anesthesia: An incision approximately 1.5 cm. in length was made through the skin and subcutaneous tissues in the mid-nasal line almost immediately above the level of the supraorbital ridges. With a Stille's bone drill, provided with a suitable guard, a round opening, about 0.8 cm. in diameter was drilled into the frontal bone. This opening was made at approximately the level of the olfactory bulbs. With a specially made electric cautery tip (0.4 cm. × 5.5 cm.), the region of the olfactory bulb and olfactory tract for a distance of about 2 cm. from the opening, was subjected to cauterization. After suturing the skin and covering the area with collodion the animals were held for a half hour in a specially designed box animal-holder to prevent them from injuring the operative field while recovering from the effects of the anesthetic. None of the animals seemed disturbed by the operation and the wounds in each instance healed nicely.