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The highly interesting observation of Bainbridge (1911) that certain aerobic and facultative anaerobic bacteria of the gelatinliquefying and non-liquefying types are -of themselves unable to initiate decomposition of purified native proteins has been fully corroborated by Sperry and Rettger (1915). The last-named authors have shown further that the putrefactive anaerobes B. puttr flcus, B. oedematis (B. oedematis-malgni, Zopf) and B.Feseri (B. anthracis-symptomatici, Kruse) are likewise devoid of this property; and that the vegetable protein edestin, like egg and serum albumin, does not undergo disintegration by direct bacterial action. It was but natural to assume, therefore, that the protein nitrogen cannot be utilized by bacteria unless it is first simplified and made available for cell nutrition through the, action of a proteolytic enzyme, strong acid or alkali, or some other cleavage-producing agent.Solutions of purified proteins were prepared by the methods now used in all biochemical laboratories and involving the-crystallization of the proteins. The test media were usually the same as those employed by Bainbridge, and contained the following ingredients, besides the protein; sodium chloride 0.5 per cent, sodium sulphate 0.2 per cent, calcium chloride 0.1 per cent and acid potassium phosphate 0.1 per cent. The only possible source of nitrogen was the protein, except in certain check tests in' which small amounts of peptone were employed. The solutions containing the purified proteins were sterilized by filtration through the laboratory Berkefeld.The test media were inoculated from 24 hour slant agar cultures of the various organisms, with the special precaution of 15 on July 16, 2020 by guest

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