2. On saturating with ammonium sulphate, a brownish precipitate is thrown down which is perfectly soluble in cold water. It consists of gelatose lactates which are evidently formed in an analogous manner, to the gelatose hydrochlorides prepared by C. Paal.[129] The gelatoses correspond to the protoses formed during the digestion of albumin. In one sample 1·3 grm. gelatose lactates per 100 c.c. was found. [129] Ber. 25, 1202; also Allen, “Comm. Org. Analysis,” iv., 466. F. Marpmann, Centralblatt f. Bakt. 2, 5, 67. 3. The filtrate from (2) was dialysed against running water for 15 hours to get rid of the ammonium sulphate. The resulting gelatin-peptones, or gelatones, amounted to 9·1 grm. per 100 c.c. In other words, the heating under pressure had transformed 87 per cent. of the original gelatin into true peptones. It may be presumed that the other and simpler nitrogenous bodies formed, are the same as those produced by the treatment of gelatin solutions by dilute mineral acids, and that the bases combine with the free lactic acid. An excellent list of these and a very interesting account of the protamines and hexones which go to form the complex albumin molecule is given in a paper by Dr. A. Kossel.[130] [130] Rev. Gen. des Sciences, 1899, p. 380. The solution of gelatone lactates and free lactic acid prepared as above, was neutralised with sodium carbonate and diluted to 1000 c.c.; it was found to be a very good medium for the growth of the bating organisms after the addition of a small quantity of potassium phosphate. In looking round for suitable means of testing the action of both pure and mixed cultures of bacteria on a practical scale, it occurred to me that the Carlsberg vessels, as used by Hansen for the pure cultivation of yeast,[131] would answer for the cultivation of bacteria also. I was unable to obtain any information on the subject, and was surprised to find that the apparatus is very little used in England. I procured two of these vessels from Jensen of Copenhagen, and found they answered very well. The bacteria were transferred from the test tube in which the original inoculation had been made to a Pasteur flask of 250 c.c. capacity containing the nutrient solution; when the growth in this flask was sufficiently vigorous the Carlsberg vessel was inoculated from it in the manner described by Hansen, and with all the usual precautions. [131] Jorgensen, the “Micro-organisms of Fermentation,” p. 20. After three days at a temperature of 37° C. the whole of the 10 litres was used for inoculating 100 litres of the nutrient medium above mentioned contained in a clean barrel standing in a room, the temperature of which was maintained at 37° C. By using this comparatively large volume of pure culture for pitching, if I may be allowed to use a familiar brewing term, the large culture was kept practically pure, although it could not be supplied with germ-free air, as in the case of the Carlsberg vessel.