The Endogenous Respiration of Bacillus cereus

This paper deals with the action of salts on respiration in the absence of substrate-the endogenous respiration of Stier and Stannard (1935). The use of substrates which permit cell division has been avoided because salts influence cell multiplication, creating difficulties in interpreting the results in terms of the effect of the salts upon respiration. Moreover, measurements of gaseous exchange in the presence of substrate may give a misleading picture of the respiratory activity of a bacterial suspension owing to the existence of concurrent anabolic reactions, even where the number of cells does not change, as in the case of washed cells (Giesberger, 1936; and Barker, 1936). The effects of the components of the buffer mixture were first assessed, since they were expected to be similar to those of other salts. Thus, the investigation was begun by studying the effect of salts in unbuffered solutions without substrate, and the data so obtained were applied to the interpretation of experiments in which the effect of salts was studied in buffered solutions.