58 A MANUAL OF BACTERIOLOGY 



Exercise 84. Study of Aerobic Organisms which Decompose Cellulose 



A study of these organisms, even in mixed cultures, is in- 

 structive in demonstrating how cellulose substances are liquefied 

 in sewage, manure, soil, and other media. 



1. Prepare the following medium and fill Erlenmeyer flasks 

 to a depth of 0.5-1 cm. 



Filter paper (in strips) 2.00 g. 



XH 4 C1 0.10 g. 



K 2 HP<) 4 0.05 g. 



CaCO 3 (chalk) 2.00 g. 



Water 100.00 cc. 



2. Inoculate the flasks with fresh horse manure or with slimy 

 mud from the bottom of a pond or river. Incubate the flasks 

 for three or four weeks at a temperature of 30-34 C. 



3. Transfers should be made with a platinum loop to other 

 flasks of sterile solution after a month. In this way the growth 

 of the cellulose-decomposing organisms is increased. It may re- 

 quire two or three transfers to get really active decomposition. 



4. The cellulose first becomes brown in color, then perforated 

 with holes. A brown color is usually imparted to the solution. 



5. Make cover-glass stains of bacteria taken from a flask in 

 Avhich cellulose decomposition is progressing. 



Exercise 85. Study of Anaerobic Organisms which Decompose Cellulose 



1. Proceed to fill Erlenmeyer flasks to the stopper (rubber) 

 with the following solution : 



Filter paper . . 20.00 g. 



CaC( > 3 (chalk) 2.00 g. 



K 2 HPO 4 0.10 g. 



MgSO 4 0.50 g. 



(NH 4 ),S0 4 (orl><> 4 ) 1.00 g. 



NaCl trace 



Water 1000.00 cc. 



2. Inoculate with fresh horse manure or slimy mud. If horse 

 manure is to be used, the filter paper may be omitted. 



3. Incubate at 30-34 0. for a month and make transfers as 

 in Exercise 84. 



