44 LABORATORY MANUAL OF MICROBIOLOGY 



3. Add decanted water, 2 per cent peptone and 0.1 per cent 

 glucose. 



4. Tube by punching through the fiUing funnel with a glass rod. 



5. Sterilize intermittently in an Arnold sterilizer. 



Five daily runs of 30 minutes each are recommended. Steri- 

 lization in an autoclave is usually a failure because of the tendency 

 of the medium to climb on to the plugs. However, if long tubes 

 are used, this medium may be sterilized in the autoclave. The 

 finished medium is nearly white with a clear supernatant liquid. 



The small amount of glucose is to stimulate growth; excess 

 would prevent or interfere with putrefaction and blackening. 

 Peptone stimulates early development and intensifies the blacken- 

 ing produced by those organisms liberating H2S. 



Medium 104 

 Nitrate Solution for Higher Green Plants 



(a) Calcium nitrate (Ca(N03)2-4H,0) 100.0 gm. 



Potassium nitrate (KNO3) 25. gm. 



Sodium chloride (NaCl) 15. gm. 



Distilled water 1,000 . cc. 



(h) Monopotassium phosphate (KH2PO4) 25.0 gm. 



Distilled water 1,000.0 cc. 



(c) Magnesium sulphate (MgS04-7H20) 50 . gm. 



Distilled water 1,000. cc. 



(d) Ferric chloride (FeCl;r6H20) 5.0 gm. 



Distilled water 250 . cc. 



Take 10 cubic centimeter portions of solutions (a), (6), and 

 (c) to 1,000 cubic centimeters of water. Add 1 to 2 drops of 

 solution (d). 



Medium 105 



Solution for Growing Higher Plants 



(a) Ammonium nitrate (NH4NO3) 32.0 gm. 



Distilled water 1,000.0 cc. 



(6) Monocalcium phosphate (CaH4(P04) 2. H2O). 10.0 gm. 



Distilled water 1,000.0 cc. 



(c) Potassium sulphate (K2SO4) 20 . gm. 



Distilled water 1,000.0 cc. 



(d) Magnesium sulphate (MgS04-7H20) 8.0 gm. 



Distilled water 1,000.0 cc. 



(e) Ferric chloride (FeCla-OHzO) . 1 gm. 



Distilled water 250 .0 cc. 



