SPECIAL MEDIA 57 
SPecIAL Mepta‘ 
Peptone Sucrose Solution (Buchanan, 1909). 
Monobasic potassium phosphate (KH2PO4).. 2.0 gms. 
Magnesium sulphate (MgS0O4-7H2O)........ 0.1 gms. 
Peptone... 02.0... cc eee ee eee 1.0 gms. 
SUCTOSC. kee ee eee ee ee 20 0 gms. 
Distilled water............0..0. 0.0.00 cea 1000 c.e. 
Hay Infusion. Macerate 15-20 gms. of finely chopped hay or 
in 1000 gms. of H2O for one or two hours. Boil for a few minutes, 
filter, tube and sterilize at 115° C. The infusion which is sometimes 
a little acid may be neutralized in the usual way. 
Beer Wort (Eyre, 1903). 1. Weigh out 250 gms. malt and put into 
a flask. 
2. Add 1000 «c.c. distilled water heated to 70° C. and close flask 
with rubber stopper. 
3. Place the mixture in a water bath at 60° C. and allow the mixture 
to stand for one hour. 
4. Strain through cheese cloth into clean flask and heat in an Arnold 
for thirty minutes. 
5. Filter through paper. 
6. Tube in 10 c.c. quantities and sterilize in an Arnold. 
Spronck’s Peptone Yeast Extract. To 5 liters of HeO add 1000 
gms. commercial yeast, not brewers’ yeast. Boil for twenty minutes 
with stirring, pour into cylindrical vessels and leave for twenty-four 
hours. Decant the cloudy liquid and add 5 gms. of NaCl and 10 gms. 
of peptone per liter. Neutralize exactly and then make alkaline to 
7 per cent with NNaOH. Filter through Chardin paper and pour 
into flasks. Sterilize at 115° C. 
Wine. Before sterilizing make neutral in the ordinary way. 
Prune Decoction. Macerate 50 gms. of prunes in 1 liter of distilled 
water and allow to stand in the ice chest until the next morning. Filter 
and tube for sterilization. 
Pea-flour Extract (Gorden et al., 1916). Take 100 gms. of pea flour 
and add 1 liter of distilled water with 100 gms. of salt. Mix and steam 
for one-half hour, stirring constantly. Allow to settle and filter, then 
sterilize and label ‘‘ saline pea extract.”’ This pea-flour extract should 
preferably be freshly made for each batch of agar. This medium was 
especially designed to replace Witte’s peptone. 
