CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



815 



2491. Simmonds' Shellaced Potato 



Constituents : 



1. Potatoes. 



2. Shellac. 

 Preparation : 



(1) Clean and boil potatoes in the usual 

 way. 



(2) Cool and tie strings on the potatoes. 



(3) Dip them in a shellac solution three 

 different times, allowing them to 

 dry about i hour between each time. 



(4) They are dry after about an hour and 

 may be stored in piles. 



Use: Preservation of potatoes. Author 

 reported that potatoes treated in this 

 manner do not lose their moisture. 

 Might be used for anaerobic growth. 



Reference: Simmonds (1897 p. 100). 



2492. Krannhals' Sliced Potato 



Constituents: 1. Potato. 

 Preparation : 



(1) Wash potatoes with water and soap 

 with a brush. 



(2) Allow them to remain in a sublimate 

 solution for a short time and rinse in 

 boiled water. 



(3) Boil the potatoes or heat about 

 2 hours in streaming steam. 



(4) Cut in thin slices, about 1 cm. thick, 

 with a sterilized knife. 



(5) Place 4 to 6 slices in a flat dish covered 

 with a projecting covering (Petri 

 dish ?). This dish contains a layer 

 of hygroscopic cotton which has been 

 saturated with 1.0% sublimate solu- 

 tion and then carefully pressed out. 

 A piece of blotting paper or a layer of 

 cotton soaked up with sterile dis- 

 tilled water may also be added if 

 incubated in the incubator. 



(6) Add either drop by drop 1 to 2% 

 aqueous solution of sodium bicar- 

 bonate on the side until a noticeable 

 adsorption has taken place or pour 

 several cc. of soda solution on the 

 bottom of the plate so that the plate 

 is scarcely covered. 



Sterilization: Place the plates for 30 min- 

 utes in streaming steam on 3 or 4 suc- 

 cessive days. 



Use: Cultivation of comma bacilli. Other 

 investigators used a medium similarly 



prepared to cultivate a large variety of 

 organisms. 

 Variants : 



(a) The author reported that medium 

 may be used without the addition of 

 soda solution or sodium bicarbonate. 



(b) Migula prepared the potatoes as 

 follows: 



(1) Peel good sound potatoes with few 

 eyes and cut in discs one centimeter 

 thick. 



(2) Wash repeatedly in water. 



(3) Place in Petri dishes. 



(4) Boil for one hour in the steamer. 



(5) On the following day steam for 

 30 minutes. 



(6) Potatoes may be cut in cylindrical 

 pieces and placed in tubes contain- 

 ing a little water and some cotton 

 in the bottom of the tube. 



(7) If the potatoes do not react slightly 

 acid, add a drop or two of 0.5% 

 citric acid to the surface of the 

 potato discs or cylinders. 



(c) Various investigators prepared po- 

 tatoes in essentially the same manner. 

 The methods employed were not suffi- 

 ciently different to those given to 

 warrant individual mention. 

 References: Krannhals (1893 p. 37), Migula 

 (1901 p. 22), Abel (1912 p. 28), Besson 

 (1920 p. 56), Abbott (1921 p. 132), Harvey 

 (1921-22 p. 118), Klimmer (1923 p. 205). 



2493. Wurtz's Potato Medium 



Constituents: 1. Potato. 

 Preparation : 



(1) Thoroly wash sound potatoes. 



(2) Place in a 1 to 1000 sublimate solution 

 for one hour. 



(3) Wash crystallizing dishes and filter 

 papers in a 1:1000 sublimate solution. 



(4) Cut the potatoes in half, and put each 

 half in one of the crystallizing dishes 

 containing a filter paper. 



Sterilization: Cover the dishes and auto- 

 clave at 125°C. for 30 minutes. 

 Use: General culture medium. 

 Variants : 



(a) Smith prepared the potatoes as 

 follows: 

 (1) Wash large sound potatoes in run- 

 ning water, using a stiff brush. 



