In the majority of the monkeys there was more or less diffuse and irregular cellular infiltration of the meninges. In most animals there was a more or less pronounced swelling, edema and lymphocytic infiltration of the choroid plexus, i.e. the cellular membrane lining the intracerebral ventricles, which led him to name the disease "lymphocytic choriomeningitis". While still doing research work on LCM in 1939, Armstrong was able, for the first time, to adapt and transmit a human strain of poliovirus (the rarer and less dangerous "Lansing" type 2 strain) from monkeys to small rodents, first to the cotton rat ("Sigmodon hispidus hispidus") and then to white mice. This accomplishment was revolutionary as it made possible the study of many aspects of infection and immunity in humans that could scarcely have been carried out with monkeys. The discovery also stimulated the renewal of efforts to adapt and establish the other immunologic types of poliomyelitis, leading to methods that resulted in the eventual developments of successful vaccines for poliomyelitis. In recognition of his achievements in polio research and prevention Armstrong was inducted into the Polio Hall of Fame in Warm Springs, Georgia. The article is mainly based on the Beeman publication, which also contains valuable photos: