Armstrong – Table of Contents

nerves. He then instilled live poliovirus into the noses of the monkeys, but the ones with
the severed nerves did not become ill. Dr. Schultz thus showed that severing olfactory
nerves of the test animals prevented the development of paralysis from poliovirus
instilled nasally.
Armstrong arrived at his conception of poliovirus infection prevention by
chemical blockade through a series of laboratory observations over several years. His
initial observations were related to postvaccinal encephalitis (see previous chapter) when
he noted that mice pre-immunized with diphtheria toxoid survived longer and in greater
numbers, when subsequently injected with vaccinia virus intracerebrally, than mice not
pre-immunized with diphtheria toxoid. He also demonstrated that mild irritation of a
rabbit’s eye with diphtheria toxin prevented the blinding effect of vaccinia virus. In his
experiments with St. Louis encephalitis, he found that he could prevent infection in mice
by the nasal route through the prior instillation of a dilute solution of alum (sodium
aluminum sulfate), an astringent mucus-coagulating chemical (8). Aware of the studies of
his contemporaries, Schultz and Gebhardt in California (7, 13) and Sabin, Olitsky and
Cox at the Rockefeller Institute (6, 12), Armstrong, and his colleague W.T. Harrison (9,
10), were able to prevent infection with intranasally administered poliovirus virus in
monkeys by chemical blockade. Since they felt that alum alone was too irritating, they
settled on a solution of equal parts alum and picric acid (trinitrophenol) to a final
concentration of 0.5 per cent of each ingredient (11). This was the mixture that was
recommended for the nasal spraying in the poliomyelitis preventive field studies that
were about to take place.