52 A MANUAL OF BACTERIOLOGY 



Various infusions of hay, wheat, cucumber, and 

 turnip, and decoctions of malt, prunes, raisins, and 

 horse-dung are used as cultivation media. They 

 are sterilised by being heated in the steam steriliser 

 for thirty minutes on three or four successive days. 

 The mucors grow well in decoctions of malt and 

 horse-dung ; various Aspergilli in a decoction of 

 malt and prune-juice ; and an infusion of hay is a 

 useful medium for the growth of Bacillus suUilis. 



Urine and other fluids of the body are used as 

 cultivation media: these are sterilised after the 

 manner described for bouillon. 



Besides the above-mentioned fluid media, there 

 are two others which are useful for the growth of 

 certain microbes and moulds. One of these is Pas- 

 teur's fluid, which contains 10 parts of pure cane- 

 sugar, 1 part of ammonium tartrate, the ash of 1 

 part of yeast, and 100 parts of distilled water. The 

 other is known as the Cohn-Mayer fluid, which con- 

 tains in 100 cc. of distilled water half a gramme each 

 of magnesium sulphate and potassium phosphate, 

 one gramme of ammonium tartrate, and 0*5 gramme 

 of tricalcium phosphate. Pasteur's and Cohn- 

 Mayer's fluids are sterilised by the method of dis- 

 continuous heating or if they are placed in sealed 

 flasks and sterilised in an autoclave, the sterilisation 

 is complete in about fifteen minutes. Both of these 

 fluids are useful media for the cultivations of the 

 various species of Torulce or yeasts. Test-tubes, 

 flasks, etc., are filled with fluid media by means of 

 sterilised pipettes ; or, better still, the fluid media 

 can be run directly into the cultivation vessels by 



