Range of Antibiotic Activity of Protoanemonin. ∗ †

Summary

1. Protoanemonin inhibited the growth of all the aerobic and anaerobic bacteria, the fungi and the protozoa tested. 2. The maximum dilution of protoanemonin which was effective against the bacteria and fungi varied from 1-6000 to 1-300,000. 3. The anti-bacterial activity of protoanemonin was independent of the acidity of the medium, the size of the inoculum and the age of the culture, within the limits tested. 4. The two protozoa were prevented from qrowing in dilutions of protoanemonin ranging from 1-200.000 to 1-1,600,000. 5. No inhibition by protoanemonin of the growth of the two bacteriophages and the influenza virus was demonstrable by the techniques employed. 6. A dilution of 1-1.000,000 protoanemonin was toxic for chicken tissue culture epithelial and fibroblastic cells.