180 CULTURE MEDIA 



media have been prepared and every bacteriologist believes 

 strongly in their future usefulness when media of wider 

 application shall have been devised. An example of this 

 type of culture media is Uschinsky's synthetic medium, of 

 which the following is one of the modifications: 



Distilled water 1000 parts 



Asparagin 4 " 



Ammonium lactate 6 *' 



■ Disodium phosphate 2 " 



Sodium chloride 5 " 



A criticism of this medium is that the elements K, Ca, 

 Mg, Fe, Mn, and S, which have been shown to be essential, 

 are not present if chemically pure salts are used in the 

 preparation. 



