CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



521 



(9) Sterilize at 115° to 120°C. for 

 30 minutes, 

 (d) Hoffmann (1912) made bacterial 

 counts of the soil on a 0.1% peptone 

 agar. 

 <e) L6hnis(1913). 



(1) Cut agar into small pieces. 



(2) Add 1.5% of (1) to bouillon. 



(3) Allow to soak for one to two hours 

 or overnight in a cool place. 



(4) Heat in the autoclave until solu- 

 tion is complete at 1.5 atmos- 

 pheres. 



(5) Filter thru cotton wool. 



(6) Sterilize in the autoclave, 

 (f) Roddy (1917). 



(1) Add 1.0 to 3.0% agar to bouillon. 

 (Shredded agar is used, cut into 

 small pieces before adding.) 



<2) Boil and stir until the agar is dis- 

 solved. 



(3) Add water to make up the loss 

 due to evaporation. 



(4) Adjust the reaction. 



(5) Filter in a warm place. 



(6) Sterilize in the autoclave. 

 <g) Bezangon (1920) . 



(1) Wash 15.0 g. of finely chopped agar 

 in water and soak for 12 hours. 



(2) Add (1) to bouillon. 



(3) Place in the autoclave at 120°C. 

 for 15 minutes. 



(4) Cool to 50°C. 



(5) Adjust the reaction to slightly 

 alkaline. 



(6) Beat up the white of an egg in 

 50.0 cc. of water. 



(7) Add (6) to (5). 



(8) Autoclave at 115°C. for 20 mmutes. 



(9) Filter while hot. 



(10) Tube. 



(11) Sterilize in the autoclave at 

 115°C. for 10 minutes. 



(h) Hilgermann and Weissenberg (1917- 

 18) cultivated nematodes on the 

 following medium. They reported 

 that nematodes appeared first after 

 4 days or possibly after 10 or 14 days. 

 Amoeba and bacteria grew at the 

 end of 24 hours. 



(1) Exact composition of nutrient 

 bouillon not given. 



(2) Adjust (1) so that it is alkaline. 



(3) Mix 10.0 cc. of (2) and 90.0 cc. of 

 water. 



(4) Dissolve 1.5 g. agar in (3). 



(5) Sterilize on three successive days 

 for 30 minutes in a steamer. 



(6) Pour in sterile petri dishes. 



(7) Moisten the plant or material 

 containing the nematodes and 

 place on the solidified agar. 



(i) Stitt (1923). 



(1) Weigh 15.0 to 20.0 g. of powdered 

 agar into a mortar. 



(2) Make a paste by the addition of 

 nutrient bouillon. 



(3) When a smooth even mixture is 

 made pour into the inner com- 

 partment of a rice cooker, and add 

 the remainder of the 1000.0 cc. 

 nutrient bouillon. Weigh the 

 mixture. 



(4) Fill the outer compartment of the 

 rice cooker with 25.0% NaCl solu- 

 tion, and boil until the solution of 

 agar is complete, (5 to 10 minutes 

 boiling). Do not stir. 



(5) Filter the agar thru a pledget of 

 absorbent cotton, or cotton be- 

 tween two layers of gauze, in a 

 funnel that has been heated with 

 boiling water. The filter-stand 

 with gauze cotton filter and flask 

 may be placed in an Arnold steri- 

 lizer for 20 minutes and then filter 

 the agar. (1.5% agar may be 

 filtered thru paper.) 



(6) Tube. 



(7) Sterilize in the autoclave or 

 Arnold. 



(j) Park, Williams and Krumwiede 

 (1924). 



(1) Dissolve 1.5% agar in 1000 cc. 

 bouillon by heating in the auto- 

 clave at 10 to 15 pounds for 

 20 minutes, or by boiling over a 

 free flame. 



(2) If boiled over a free flame make up 

 the loss in weight by the addition 

 of water. 



(3) Adjust the reaction. 



(4) Cool to 50 °C. and add one egg. 



(5) Heat in the autoclave at 10 to 

 15 pounds for 30 minutes or Arnold 

 sterilizer for one hour. Filter. 



