CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



731 



10.0% gelatin (1.0 to 2.0% glucose 

 may be added). 



(7) Neutralize carefully by the addi- 

 tion of concentrated Na2C03 until 

 litmus paper is colored violet. 



(8) Add soda solution as desired. 

 Generally 10.0 cc. of 15.0% soda 

 solution is added per liter. 



(9) Boil for 30 minutes in the steamer. 



(10) Filter thru paper. 



(11) The gelatin should be perfectly 

 clear. If not cool to 40°C., and 

 mix thoroly with the white of an 

 egg. 



(12) Boil again for a short time. 



(13) Filter. 



(14) Distribute in tubes or flasks. 



(15) Sterilize on 2 successive days in 

 flowing steam for 20 minutes each 

 day, and for 10 minutes on the 

 third day, or for 15 minutes on 

 each of 3 successive days. Cool 

 quickly after each heating. 



(g) Roux (Thoinot and Masselin 1902). 



(1) Macerate 500.0 g. of finely chopped 

 beef in a liter of water for several 

 hours. 



(2) Pass thru a linen cloth and express 

 the juice from the meat. 



(3) Add 10.0 g. peptone, 5.0 g. NaCl 

 and 100.0 g. of light colored gelatin 

 to (2). 



(4) Heat in a water bath not above 

 60°C. to dissolve the gelatin. 



(5) Add soda to make slightly alkaline. 



(6) Heat in steam at 100° for an hour. 



(7) Filter. 



(8) If not clear, cool to 50°C. and add 

 the white of an egg and heat again 

 to 100°C. 



(9) Filter while hot thru wet Chardin 

 paper. 



(10) Tube in sterile tubes. 



(11) Sterilize for 15 minutes on each of 

 3 successive days at 100°C. 



(h) Thoinot and Masselin (1902). 



(1) Macerate 500.0 g. of lean beef with 

 a liter of water. 



(2) Express the juice and pass thru a 

 linen cloth. 



(3) Boil several minutes. 



(4) Filter thru moistened filter paper. 



(5) Add 10.0 g. peptone, 5.0 g. NaCl 

 and 100.0 g. gelatin. 



(6) Heat over a small flame or on a 

 water bath until the gelatin is com- 

 pletely dissolved. 



(7) Make slightly alkaline. 



(8) Heat for 5 minutes at 113-114°C. 

 in the autoclave and filter while 

 hot thru Chardin paper. 



(9) Distribute as desired. 



(10) Sterilize at 112°C. for 25 minutes. 

 (i) Frost (1903). 



(1) Remove all the fat and connective 

 tissue from 500.0 g. beef and 

 mince or use hamburger steak. 



(2) Add 1 liter of distilled water to (1), 

 shake thoroly and set in the ice 

 chest for 12 to 24 hours. 



(3) Squeeze thru a cloth and add 

 enough distilled water to make one 

 liter. 



(4) Add 1.0% peptone (Witte) 0.5% 

 NaCl and from 10.0 to 15.0% of the 

 best gold label sheet gelatin. 

 (Add 10.0% gelatin in winter and 

 15.0% gelatin in summer.) 



(5) Weigh the solution and the vessel. 



(6) Heat until solution is complete. 



(7) Neutralize to phenolphthalein. 



(8) Boil 5 minutes and restore the 

 weight lost by the addition of dis- 

 tilled water. 



(9) Test the reaction, and readjust if 

 necessary. 



(10) Boil until the albumin coagulates 

 and floats in the clear liquid. 



(11) Filter thru cotton supported on a 

 coil of wire using a suction pump 

 to hasten filtration. 



(12) Add 5.0 cc. (0.5%) of a normal 

 HCl solution. 



(13) Tube. 



(14) Sterilize in the steamer for 30 

 minutes on 3 consecutive days or 

 in the autoclave at 110° for 15 

 minutes. 



(j) Frost (1903). 



(1) Remove all the fat and connective 

 tissue from 500.0 g. of beef and 

 mince, or use hamburger steak. 



(2) Add 1 liter of distilled water. 



(3) Place in a vessel for cooking and 

 cook for 30 minutes at about 70°C. 



(4) Filter thru paper and make up to 

 1 liter. 



(5) Add 1.0% peptone (Witte) 0.5%> 



