198 



BACTERIA IN RELATION TO PLANT DISEASES. 



Maasscn's Culture-Fluid. 



Malic acid 7 



Distilled water 100 



Neutralize to litmus exactly with ^ per cent 

 potassium hydrate. 'Make up to 1,000 cc. with 

 distilled water and add : 



Asparagin 10.0 



Secondary sodium phosphate 5.0 



Magnesium sulphate 2.5 



Sodium hydrate 2.5 



When dissolved add o.oi gram of calcium 

 chloride. 



To this may then be added grape-sugar or any 

 other carbon food desired. 



Proskauer and Beck's Culture-Fluid. 



Distilled water 1,000.00 



Commercial ammonium car- 

 bonate 3-5 



Primary potassium phosphate.. 1.50 



Magnesium sulphate 2.50 



Glycerin i5-o 



Mackcnsie's Culture-Fluid. 



Acid ammonium tartrate. 

 Bipotassium phosphate... 



Potassium sulphate 



Sodium chloride 



Glucose 



Lactose 



Glycerin 



Water . 



1.5- 



2.5 



i.5 



5 



5-0 



5-0 



iS-O 



1,000.0 



This is rendered alkalin to phenolphthalein 

 with normal soda solution. 



Culture-Medium for Luminous Bacteria. 



(Molisch., /. c. p. 87.) 



Water 1,000.000 



Gelatin 100.000 



Sugar 20.000 



Peptone 10.000 



Dipotassium phosphate .250 



Magnesium sulphate .250 



Enough sodium hydroxid to render the me- 

 dium feebly alkalin. On this substratum the 

 bacteria grow feebly and are not luminous until 

 sodium chloride or some equivalent substance is 

 added (usually 3 per cent). Then they grow 

 well and become luminous. 



Winogradsky-Sleskin Silicate Jelly. 



Ammonium sulphate 0.40 



Magnesium sulphate 05 



Potassium phosphate .10 



Sodium carbonate 0.60- .90 



Calcium chloride Trace 



Silicate jelly 100.00 



The salts are dissolved separately in the least 

 possible water, and added to the dialyzed acid. 



(For further observations on silicate jelly see 

 p. 36.) 



Nitrogen-free Medium for Bacteria. 



Triple-distilled water 1,000.000 



Cane-sugar 5.000 



Monopotassium phosphate. . . . 2.000 



Magnesium sulphate .100 



Sodium chloride .500 



All chemically pure, in scrupulously clean 

 flasks. The water should be freshly distilled, 

 kept in glass-stoppered bottles, and tested fre- 

 quently with Nessler's solution for presence of 

 ammonia. 



Giltay & Aberson's Culture-Medium for Deni- 

 trifying, Organisms. 



Distilled water, t 1,000.0 



Potassium nitrate 2.0 



Asparagin i.o 



Magnesium sulphate 2.0 



Citric acid 5.0 



Monopotassium phosphate 2.0 



'Calcium chloride .2 



Ferric chli >riik> 2 gtts. 



The acid should be neutralized by the addition 

 of potassium hydrate. 



This medium is a modification of that of 

 Gayon and Dupetit, less nitrate being used and 

 the neutralization being made with potash in- 

 stead of ammonia. In preparing this fluid the 

 asparagin and the nitrate of potash are dissolved 

 in 250 cc. of water ; the other substances are dis- 

 solved in 500 cc. of water, and after the citric 

 acid has been neutralized the two fluids arc 

 mixed, cooled to 15 C., and sufficient water 

 added to make I liter. When the nitrate of 

 potash and the asparagin are dissolved along 

 with the other salts a decomposition occurs, and 

 the liquid is browned from the presence of 

 nitrous acid, which should be avoided. Some 

 carbonate of lime is also added to the culture 

 fluid. Instead of asparagin, 2 grams of dextrose 



