Bacillus Typhosus

Coulthard for amoebicidal action. Each kind of activity increases to a peak as the series is ascended and then diminishes. In the 0-n-alkyl series the peak is at 0-n-butylharmol for Bacillus typhosus, at 0-n-amyl-harmol for Staphylococcus aureus and at 0-n-nonylharmol for Entamoeba histolytica. In the 0-io-diethylaminoalkyl series the peak for B. typhosus is at 0-to-diethylaminononylharmol. No trypanocidal or anti-malarial action was observed in a selection of the compounds tested. ... 

From recalculations of published data and also from measurements of the potency of many different compounds, Ferguson concluded that, within reasonable limits, substances present at approximately the same proportional saturation (that is with the same thermodynamic activity) in a given medium have the same biological potency. For example. Table 5.17 shows that while the bactericidal concentrations against Bacillus typhosus vary widely (0.0022-3.89 mol dm ), the thermodynamic activities vary within a relatively restricted range (0.11-0.76). 

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