The latent period of growth or "lag," first recognized by Mfiller in 1895,1 is the time interval between the inoculation of a medium and the beginning of growth at the max imum rate. Chesney concluded that the latent period in the growth of bacteria is an expression of injury which the bacterial cell has sustained from its previous environment3 This conclusion was based upon the observations th...

1. The optimum hydrogen ion concentration for growth of pneumococcus is pH 7.8. 2. In broth cultures growth of pneumococcus continues until a final hydrogen ion concentration of about pH 5.0 is reached, if sufficient fermentable carbohydrate' (above 0.4 per cent) is present. Apparently this acidity is sufficient in itself to stop growth. 3. If less carbohydrate is present in the medium growth c...

1. The optimum hydrogen ion concentration for the growth of the various types of pneumococcus is a pH of about 7.8. 2. The limiting hydrogen ion concentrations for the growth of pneumococcus are a pH of 7.0 and a pH of 8.3. 3. Phosphates used in adjusting reactions of media retard growth if present in a concentration greater than 0.1 molecular. 4. Culture media for pneumococci should, therefore...

1. The rate of growth of fibroblasts is markedly modified by slight changes in the hydrogen ion concentration of the medium. The curves expressing the rate of growth in function of the hydrogen ion concentration of the medium are nearly symmetrical on both sides of the maximum. 2. The optimum growth of fibroblasts occurs at pH 7.4 to 7.8. A slight change from this reaction has a remarkable infl...

Union of Pure and Applied Chemistry (IUPAC) contained recommendations for names and symbols for quantities in chemistry and physics (1). The recommendation concerning the writing of the name (symbol) of a given chemical quantity was exemplified as follows: V(K2S04, 0.1 mol dm3 in H2O, 25#{176}C) = 48 cm3 mol-'. It was up to the reader to interpret this as the molar volume of potassium sulfate i...

With the introduction of Cullen’s calorimetric method (1) of estimating the hydrogen ion concentration of blood serum or plasma, it seemed possible for every laboratoryto have a methodemploying minimum material and apparatus and yet secure reliable results. It is generally conceded that the results obtained by the method on normal human plasma or serum agree very well with the true pH as determ...

Aquatic green plants can assimilate carbon dioxide in solutions of widely varying hydrogen-ion concentration. Our purpose in investigating the rate of photosynthesis as a function of this factor was to clarify the interpretation of experiments in carbonate mixtures, where the concentrations of carbonate and bicarbonate ions and of free carbon dioxide all vary with the hydrogen-ion concentration...

The purpose of the present study has been to determine the change in the resistance of corpuscles to saponin with changes in pII., the acids employed being the common inorganic acids. Ponder (1) has shown that the rate of saponin hemolysis is increased in the presence of certain acids and has applied the equation Cl = R (C, + g) to systems in which an acid is the accelerating agent. Details of ...