PASTEUR'S, COHN'S, MIQUEVS FLUIDS. m 



modification for their cultivation ; and various slight alterations in its 

 composition render it of great value in the culture of several of the 

 other groups of micro-organisms. 



Pasteur's Fluid. 



59. Pasteur's fluid consists of — 



Distilled water, . . looo'o parts. 



Pure cane sugar, . . ioo"o ,, 



Ammonium tartrate, . . lo'o „ 



Ash of yeast, . . 075 ,, 



This formula has a special interest attaching to it, as it is that of 

 the first synthetically prepared medium employed in the cultivation 

 of micro-organisms. 



Cohn's Fluid (as most recently modified.) 



60. This consists of — 



Distilled water, . . . 200 parts. 



Tartrate of ammonium, . . 20 „ 



Phosphate of potassium, . . 20 „ 

 Sulphate of magnesium, 10 ,, 



Tribasic phosphate of lime, . . o'l „ 



MiquePs Fluid. 



61. Whilst disparaging the use of Liebig's extract of meat as a 

 nourishing medium, Miquel ^ recommends an infusion prepared 

 according to the following formula -.-^ 



Boil I kilogramme of lean beef in 4 litres of distilled water, for 



five hours. 

 Strain and neutralise with caustic soda solution. Add 40 gram- 

 mes of common salt (10 gr. per litre). 

 This infusion should be sterilised by discontinuous steaming in stock- 

 flasks of convenient size, and incubated thoroughly before using it as 

 a cultivating medium. 



* " Les organisms vivants de I'atmosphere," p. 152. 



