756 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



(b) Migula prepared the medium as 

 follows: 



(1) Prepare potato infusion from 1 

 liter of water and 500.0 g. of 

 potato. 



(2) Boil (1) with nutrient gelatin 

 (amount not specified). 



(3) Add 2.5 to 3.0 cc. of 0.1 normal 

 NaOH to each 10.0 cc. of (2). 



(4) Filter. 



(5) Sterilize (method not given). 



(6) When ready for use, pour into a 

 flask, add 1.0% KI and the water 

 under investigation. 



(7) Pour into plates. 



(c) Smith prepared the medium as 

 follows: 



(1) Grate 500.0 g. of pared potatoes 

 and place the pulp in the refrig- 

 erator 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 evapora- 

 tion to that necessary to properly 

 dilute the 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. 



(d) Ball gave the preparation of the 

 medium as follows: 



(1) Mash 500.0 g. of peeled and washed 

 potatotes, and press thru a fine 

 cloth. 



(2) Allow the juice to settle. 



(3) Filter. 



(4) Cook for one hour. 



(5) Add 10.0% gelatin to (4). 



(6) Add 2.5 cc. of 1/10 normal NaOH 

 and 1.0% KI. 



(7) Sterilization not specified. 



(e) Bezan^on gave the following method 

 of preparation: 



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



(2) Add (1) to a liter of water and 

 allow to soak for several hours. 



(3) Allow to settle. 



(4) Decant and filter. 



(5) Autoclave for 10 minutes. 



(6) Add 150.0 g of gelatin and melt on 

 a salt water bath. 



(7) Adjust the reaction to a slight 

 acidity. 



(8) Sterilize at 150°C. 



(9) Filter. 



(10) Flask in 100.0 cc. lots. 



(11) When ready for use add 1.0 g. of 

 KI and distribute in tubes. 



(12) Final sterilization not given. 

 References: Eisner (1896 p. 29), Grimbert 



(1896 p. 723), Migula (1901 p. 23), Smith 

 (1902 p. 78), Ball (1919 p. 82), Bezangon 

 (1920 p. 340). 



2337. Holz's Potato Gelatin 



Constituents : 



1. Potatoes. 



2. Gelatin. 

 Preparation : 



(1) Thoroly wash potatoes. 



(2) Cut out the eyes and all rotten 

 parts of the potatoes. 



(3) Peel and wash the potatoes in tap 

 water. 



(4) Rub the potatoes to a pulp on an 

 ordinary kitchen grater. 



(5) Filter the juice thru a clean towel 

 and press the pulp free from juice. 



(6) Place the juice in a flask, plug with 

 cotton and allow to stand for 24 

 hours at 10°C. 



(7) Filter, the juice has turned brown. 



(8) Heat in the steamer for 30 minutes 

 and filter again. 



