Full text loading...
Abstract
Summary: The effect of various conditions on the rate of death of Bacterium coli and of Streptococcus faecalis in dilute buffer solutions was followed by making colony counts at intervals during prolonged periods of incubation and then constructing mortality curves. The form of these curves was characteristic for each organism. Of the pH values investigated (approximately 5, 6, 7 and 8) both organisms were least viable in the range 6 to 7. Strep, faecalis was not affected by the degree of oxygenation of the water but Bact. coli died much more rapidly under anaerobic than under aerobic conditions.
Growth of Bact. coli was observed with as little as 0·28 part per million organic matter in solution. A much higher concentration of nutriment was required for growth of Strep. faecalis; with a concentration slightly below that required for growth the viable population remained virtually stable for a long period. The rate of death depended on the age of the cells at the time of immersion in water.
- Received:
- Published Online: