CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



705 



sufficient moisture to prevent its drying 

 up under ordinary conditions and was 

 not liquefied by fast growing types. 

 Reference: Williams and Burdick (1916 p. 

 413). 



2184. Burger's Basal Lead Acetate Agar 



Constituents : 



1. Water 1000.0 cc. 



2. Agar 30.0 g. 



3. Lead acetate 1.0 g. 



4. Meat extract 4.0 g. 



Preparation : 



(1) Dissolve 2, 3 and 4 in 1. 



(2) Suspend 1.0 g. of one of the added 

 nutrients in physiological salt solu- 

 tion and add 3.0% Na2C03. 



(3) Add (2) to melted (1), cooled to 56°C. 

 Sterilization: Not specified. 



Use : To study the production of hydrogen 



sulphide. 

 Added nutrients: The author suspended 

 1.0 g. of one of the following in physio- 

 logical salt solution: 

 cystine 

 taurine 



sodium taurocholate 

 Reference: Burger (1914 p. 202). 



2185. Hiss' Extract Agar 



Constituents : 



1. Distilled water 1000.0 cc. 



2. Extract, Liebig's 5.0 g. 



3. NaCl 5.0 g. 



4. Agar 15.0 g. 



Preparation : 



(1) Dissolve agar in water by boiling 

 over free flame for 30 to 45 minutes. 



(2) Dissolve Liebig's extract and sodium 

 chloride in (1). 



(3) Clarify by the coagulation of two egg 

 whites in (2). 



(4) Filter thru cotton. 



(5) Reaction is 0.75% acid to phenol- 

 phthalein. 



(6) Tube in 10.0 cc. lots. 

 Sterilization: Sterilize in the Arnold in the 



usual manner on three successive days. 

 Use: Differentiation of typhoid, colon 

 and allied forms. The author reported 

 that typhoid colonies were threaded. 

 Colon colonies formed no threads, surface 

 colonies dark at center, light at periphery. 

 Little difference, if any, if salt be omitted. 



Other authors used similar media for the 

 cultivation of amoeba, parasitic flagellata 

 and ciliata, cladothrix and protozoa. 

 Variants : 



(a) Hiss omitted the NaCl. 



(b) Musgrave and Clegg cultivated 

 amoeba on a medium containing 20.0 

 g. agar, 0.3 toO.5 g. NaCl and 0.3 to 0.5 

 g. beef extract per liter. The original 

 reaction of the medium being 1.5% 

 alkaline before sterilization, and 

 1.0% alkaline following sterilization. 

 The authors reported that in some 

 cases even smaller amounts of salt 

 and extract were more desirable — 

 especially when amoeba were growing 

 in company with some saprophytic 

 bacteria. 



(c) Linde isolated cladothrix {Clado- 

 thrix dichotoma) on a medium con- 

 taining 15.0 g. agar and 5.0 g. meat 

 extract per liter. Linde reported 

 that contaminating forms grew but 

 cladothrix soon overgrew them. The 

 best solid medium for cultivation is 

 10.0 g. agar with 0.5 g. meat extract 

 in 1000.0 cc. water. 



(d) Zikes cultivated Cladothrix dicho- 

 toma and Cladothrix natans on 

 Linde's medium, containing 5.0 g. 

 meat extract and 10.0 g. agar per 

 liter. 



(e) Malm (Besson) prepared the medium 

 as follows: 



(1) Dissolve 5.0 g. Liebig's meat 

 extract (or 20.0 g. Cibils) in 1000.0 

 cc. water. 



(2) Soak 20.0 g. of chopped thread 

 agar in cold water for several 

 hours. Squeeze the water thru a 

 cloth. 



(3) Heat (2) in (1) at 100°C. until the 

 agar is dissolved. 



(4) Readjust the reaction if necessary. 



(5) Allow to cool to 55 or 60°C. 



(6) Beat the white of an egg in 100.0 

 cc. of water and add to (5). 



(7) Mix well. 



(8) Autoclave at 120°C. for one hour. 



(9) Filter thru a moistened Chardin 

 filter using a hot water funnel. 



(10) Tube. 



(11) Sterilize at 115° for 20 minutes. 



(f) Harvey cultivated protozoa on a 



