SYNTHETIC CULTURE MEDIA. 



199 



may be added. If the latter is used the fluid 

 must not contain the least excess of potassa; 

 otherwise when it is sterilized there will be more 

 or less humification. (Recherches sur un mode 

 de denitrific.it ion, etc. Archives neerlandaises 

 des Sci. Ex. et Nat, Tome XXV, 1892, pp 341- 

 361.) 



Winogradsky's Culture-Medium for Nitrogen- 

 Assimilating Soil-Bacteria. 



Twice-distilled water 1,000.00 



Potassium phosphate i.oo 



Magnesium sulphate 0.50 



Sodium chloride 01 to 0.02 



Iron sulphate 01 to .02 



Manganese sulphate 01 to .02 



Dextrose 2 o 1040 



To this should be added a small quantity of 

 pure calcium carbonate, 30 or 40 grams per liter 

 is sufficient. The carbonate is freshly washed 

 in boiling water and added in paste or dried 

 rapidly and preserved in flasks with ground- 

 glass stoppers. It is recommended that the sec- 

 ond distillation of the water be made with car- 

 bonate of soda and that pure salts be obtained 

 by repeated crystallizations. It is probable that 

 monopotassium phosphate is meant by fliosphat 

 de fotasse. (Recherches sur 1'assimilation de 

 1'azote libre de I'atmosphere par les microbes, 

 Archives des Science Biologiques, Tome III, 

 p. 304, St. Petersburg, 1895.) 



Bcycrinck's Agar for Cultivation of the Nitrite 

 Bacteria. 



Ordinary agar is added to distilled water, 

 heated until it passes into solution, and poured 

 into Erlenmeyer's flasks, where it is left to 

 solidify. When cold the flasks are filled with 

 distilled water (not necessarily sterile) and set 

 away. After several changes of water and the 

 lapse of one or two weeks the soluble organic 

 substances will have been absorbed out of the 

 agar, and to it may now be added the inorganic 

 nutrient substances desired, after which it is 

 sterilized. Along with the nutrient substances 

 some pure precipitated calcium carbonate should 

 be added. The sterile agar may then be solidi- 

 fied in Petri dishes, test-tubes, etc. Beyerinck 

 considers this medium better for isolation of the 

 nitrite ferment than the silicate jelly. Hydro- 

 gen ammonium sodium phosphate (NH, Na- 

 HPCX-KH-O) is recommended as the best one 

 nf the ammonium salts for addition to the agar, 

 because, upon cooking, the agar is not attacked, 

 and consequently additional soluble substances 



are not liberated from it. (Beyerinck: Kultur- 

 versuche mit Amoben auf festem Substrate. 

 Centralb. f. Bakt., i Abt, Bd. XIX, 1896, pp 

 257-267.) 



Winogradsky's Nutrient Agar for Isolation of 

 Nitrate Bacteria. 



Tap-water T ,ooo 



Agar (thoroughly washed) 15 



Di-potassium phosphate 0.05 



Fused sodium carbonate i 



Sodium nitrite (Merck) 2 



(Centralb. f. Bakt, 2 Abt, Bd. V, 1899, pp. 

 537-549-) 



Winogradsky & Omclianski's Fluid Culture- 

 Medium for Isolating the Nitrate Bacteria from 

 Soils. 



Distilled water 1,000.0 



Magnesium sulphate .3 



Ferrous sulphate .4 



Sodium chloride .5 



Di-potassium phosphate .5 



Fused sodium carbonate i.o 



Sodium nitrite (Merck) i.o 



Transfers through a series of flasks are neces- 

 sary in order to isolate the organism. (Cen- 

 tralb. f. Bakt, 2 Abt, Bd. V, 1899, pp. 537-549.) 



Winogradsky & Omclianski's Fluid Culture- 

 Medium for Isolating the Nitrite Bacteria from 

 Soils. 



Distilled water 1,000.0 



Ferrous sulphate .4 



Magnesium sulphate .5 



Di-potassium phosphate i.o 



Sodium chloride 2.0 



Ammonium sulphate 2.0 



The cultures are made in broad-bottomed 

 flasks in 50 cubic centimeters of the fluid, to 

 each of which about Y 2 gram of magnesium car- 

 bonate is added. It is necessary to transfer 

 through a series of flasks in order to obtain 

 pure cultures. If the organism does not grow- 

 well on the start, additional ammonium sul- 

 phate may be added, viz, I cubic centimeter of a 

 10 per cent solution to each flask. (Centralb. 

 f. Bakt, 2 Abt, Bd. V, 1899, pp. 537-549.) 



Dubois' Fluid Medium for Luminous Bacteria. 

 (See '93 Dubois, Bibliog, XXVII.) 



Kuntze's Medium for Bacillus Prodigiosus. 

 (See 'oo Kuntze, Bibliog, XXIII.) 



