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March 17, 1945


JAMA. 1945;127(11):652. doi:10.1001/jama.1945.02860110032010

Experimental confirmation of clinical experience1 that penicillin is ineffective against virus diseases is reported by Parker and Diefendorf2 of the Western Reserve University School of Medicine. Equine encephalomyelitis, meningopneumonitis, psittacosis, St. Louis encephalitis and two strains of vaccinia virus were tested by these investigators. Two methods were used to determine viruscidal effects. By the first method the virus was cultivated in Rivers-Li culture medium3 consisting of a suspension of chick embryonic cells in Tyrode solution, with or without penicillin. After five days' incubation the penicillin containing cultures and the nonpenicillin controls were titrated for virus. By the second method, both virus and penicillin were injected into the yolk sac of intact chick embryos or placed on the chorioallantoic membranes. Development of lesions on the membrane or death of the embryo was taken as a criterion of virus growth.

The results of experiments in which viruses were cultivated