90 
1 gm. Sodium asparaginate. 
1 gm. Dextrose. 
.2 gm. Magnesium sulphate. 
1.5 gm. (NH,H2PO,) ammonium biphosphate. 
.1 gm. Calaum chloride. 
.1 gm. Potassium chloride. 
Trace Ferrous chloride. 
1,000 ec. Distilled water. 
Sort Extract (UNHEATED). 
15 grams of best agar dissolved in 1,000 cc. of solution made as follows: 
Two kilos of the brown loam soil were placed in a glass bottle, and 5 
liters of distilled water added, the bottle was shaken at intervals and at end 
of 16 hours the mixture was filtered. One thousand ce. of the filtrate was 
used in place of distilled water in making up this media. 
Som Extract (AUTOCLAVED). 
Fifteen grams ot best agar dissolved in 1,000 cc. of solution made the 
same as the soil extract (unheated), except that the two kilos of soil were 
wet well and heated under 25 lbs. pressure in the autoclave for three hours. 
Soil and agar, leaf extract and agar, and wheat straw extract. 
These three media were made as follows: To 15 gms. of the best agar 
were added 10 gms. of the material desired and 1,000 ce. distilled water. 
The mixture was heated in a double boiler until the agar was dissolved. 
After making up to volume the media was filtered and tubed. 
OTHER MepIia. 
To 15 gms. of best agar was added 1 gm. per liter of chemicals appearing 
as part of the name of the media and 1,000 ce. of distilled water. 
Figure 1 expresses graphically the acidity of the various media. The 
procedure in titrating was as follows: To about 125 ec. of distilled water 
that has been boiling about 3 minutes in a Jena erlenmeyer flask was added 
50 ec. of the media by means of a tall 50 ce. graduate (of small cross-section). 
Two drops of phenolpthalein solution was added and titration made with 
tenth normal sodium hydroxide. The only media neutralized at all was H. J. 
Conn’s sodium asparaginate agar, and this was done with half normal soda, 
using a pipette graduated to one-twentieth of a ce. 
