The Bactericidal Properties of Blood Serum: I. The Reaction-Velocity of the Germicidal Action of Normal Rabbit-Serum on B. coli commune and the Influence of Temperature thereon

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Abstract
1. The action in vitro of normal rabbit-serum upon B. coli commune consists usually of three or more phases, the duration of which is inversely related to temperature.2. The latent period which occurs on first mixing bacteria and serum is followed by a period of bacterial growth, which in its turn yields to a period of bactericidal action. This may remain final or may be succeeded by a second period of growth.3. The germicidal action, both in case of normal rabbit-serum upon B. coli commune and of normal goat-serum upon B. typhosus, takes place in accordance with a logarithmic law so that death-rate remains proportional to the concentration of surviving bacteria.The bactericidal action of serum thus falls into line with all other cases of disinfection, hitherto investigated.4. The temperature coefficient of the bactericidal action of serum is low in comparison with that found for other germicides, being 2·84 per 10°C. rise in temperature for normal rabbit-serum and B. coli commune and 1·93 in the case of normal goat-serum and B. typhosus.5. Growth of B. coli commune in rabbit-serum takes place logarithmically so that the concentration of living bacteria after equal intervals of time form terms of a geometrical series.The calculated value of the generation-time is slightly greater than that obtaining in broth at the same temperature.6. The influence of temperature upon rate of bacterial growth in serum is comparable with the effect upon growth in other media. The generation-time is decreased 2·01-fold for a rise in temperature of 10°C.7. The separate processes of bacteinal growth and death in serum being similarly influenced by temperature, there is no support for the view that the significance of fever might be concerned with a tendency to encourage either process relative to the other.