In a previous publication (1) allusion was briefly made to the difficulty which had been experienced in preserving sterility in material during a series of auto-digestion experiments. Contrary to expectation, it was found that a mixture of ground barley and water, when incubated at 37° for a few days, developed, even in the presence of chloroform or toluol in excess, a strong butyric acid fermentation.

Since this question was one not only of vital interest to the work in hand but also of great general importance, it was decided to carry out a series of experiments in the endeavour to determine the position with regard to the use of antiseptics in the study of biochemical processes.