CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



757 



(9) Add 50.0 g. gelatin to 400.0 cc. of the 

 filtrate, and heat for 45 minutes in 

 the steamer. 



(10) Tube in 5.0 or 10.0 cc. lots in sterile 

 test tubes. 



(11) The medium is clear and brown. 

 The reaction is acid. 10.0 g. re- 

 quires 1.6 cc. N/1 alkali to neutralize 

 to litmus. 



Sterilization : Sterilize on 3 successive days 

 for 15 minutes each day in streaming 

 steam. 



Use: Isolation of Bacillus typhosus and 

 Bacillus coli communis. 



Variants : 



(a) Holz added 0.05% phenol to inhibit 

 molds, liquefiers and other forms. 



(b) Smith prepared the medium as 

 follows: 



(1) Grate 500.0 g. of pared potato and 

 place the pulp in the refrigerator 

 in a porcelain dish over night. 



(2) Express the juice from the pulp. 



(3) Filter several times thru a layer of 

 absorbent cotton or thru animal 

 charcoal. 



(4) The filtrate should now be titered 

 with decinormal sodium hydroxide 

 solution to determine its reaction 

 and the amount of water which will 

 be required to be added to reduce 

 its acidity to the standard. In 

 this quantity of water is now 

 boiled the amount of gelatin 

 required to make 10.0% proportion 

 of the gelatin when the potato 

 juice shall have been added, the 

 reaction of the gelatin being 

 corrected to neutral point after 

 it has been dissolved (and before 

 adding the potato juice) by means 

 of normal sodium hydroxide solu- 

 tion. This done and the bulk of 

 the fluid corrected for evaporation 

 to that necessary to properly 

 dilute potato juice, the latter is 

 slowly added to the gelatin and 

 mixed, and the whole boiled for 5 

 to 10 minutes. 



(5) Filter. 



(6) Tube. 



(7) Sterilize by the intermittent 

 method. 



(c) Zikes (Will) prepared a medium as 

 follows: 



(1) Peel clean potatoes and grind in 

 the grinding machine. 



(2) Press out the juice by means of a 

 hand press. 



(3) Add bone black and heat and 

 finally filter while hot. 



(4) Add 10.0% gelatin and prepare the 

 potato water gelatin in the usual 

 manner. (Method not given.) 

 (Carrots may be handled in the 

 same way. Heat the carrot juice 

 in the steamer before filtering.) 



(d) Eisner (Tanner) gave the following 

 nethod: 



(1) Peel and grate 500.0 g. of potato. 



(2) Grind (1) and soak in distilled 

 water for 12 hours. 



(3) Strain and allow to stand. 



(4) Filter to clear. 



(5) Make up to one liter. 



(6) Dissolve 15.0% gelatin in (5). 



(7) Adjust the reaction to acid (indi- 

 cator not specified). 



(8) Sterilize (method not given). 



(e) Eisner (Besson) prepared the medium 



as follows: 



(1) Thoroly wash, grate and peel 

 potatoes. 



(2) Soak 500.0 g. of (1) in a liter of 

 water for 4 hours. 



(3) Pass thru a sieve. 



(4) Allow to settle over night. 



(5) Decant. 



(6) Make up the decanted liquid to 

 1000.0 cc. 



(7) Dissolve 150.0 to 200.0 g. of gelatin 

 in (6) by heating gently. 



(8) Boil for several minutes. 



(9) Add soda solution until the re- 

 action is but only slightly acid. 



(10) Heat at 115° for 5 minutes. 



(11) Filter thru paper, in the autoclave 

 or use a hot water funnel. 



(12) Tube. 



(13) Sterilize at 110° for 20 minutes. 

 References: Holz (1890 p. 159), Smith 



(1902 p. 78), Will (1907 p. 435), Tanner 

 (1919 p. 60), Besson (1920 p. 40). 



2338. Goadby's Glycerol Potato Gelatin 

 (Tanner) 



Constituents: 



1. Glycerol potato broth 1000.0 cc. 



2. Gelatin 100.0 g. 



