BLOOD AND BLOOD SERUM MEDIA 69 
When these substances are thoroughly dissolved, add 40 ec. of 
glycerol. Tube and sterilize. 
Uschinsky’s Medium (Smith’s 1905 Modification). 
Distilled water................... 00.00 eee 1000 e.c. 
Ammonium lactate..... Lecce eee e nee aeee 5 gms. 
Sodium asparaginate ..........0. 00... 0 0c eee 2.5 gms. 
Sodium sulphate, NaSO4-10H2O............ 2.5 gms. 
Sodium chloride, NaCl..............0....... 2.5 gms, 
Dipotassium phosphate, KeH} Og... 2.220... 2.5 gms. 
Caleium chloride, CaCle.............0. 0085. .010 gm. 
Magnesium sulphate, MgSO4............4.. .010 ym. 
Recommended for use with starch jelly. 
Bioop AND BLoop SERUM Mepra 
Blood Serum. Beef blood should be collected at the abattoir in 
clean containers and placed in the refrigerator until a clot has formed. 
The clear serum should then be decanted or better siphoned off into a 
sterile flask. For the preparation of Loeffler’s blood serum, 1 part of 
glucose broth is mixed with 3 parts of the serum. This is then dis- 
tributed into test tubes (or other containers) and placed in the inspis- 
sator in a slanted position. Small tin ointment boxes make good con- 
tainers when the blood serum is to be used for routine diphtheria exami- 
nations. After coagulation has been accomplished, the boiled serum 
should be sterilized in the autoclave at a temperature of about 112° C. 
If desired, intermittent heating in the Arnold may be used. 
Blood Agar (Besson). 1. Melt tubes of glycerol agar and cool to 
40° C. 
2. Add to each tube a small quantity (1 ¢.c.) of blood from a rabbit’s 
artery. Mix without shaking the tubes and cool in sloping position. 
A solution of hemoglobin may be used instead of blood. 
Blood Agar for Streptococci (Becker, 1916). Standard agar used in 
water analysis is placed in quantities of 40 to 100 ¢.c. in flasks. These 
are heated until the agar is melted, and then cooled to 45° or 50° C. 
One cubic centimeter defibrinated human blood is added for each 6 c.c. 
of the agar base and the whole is thoroughly shaken. Approximately 
7 c.c. are used for each plate. Surface streaks are made and observa- 
tions made after twenty-four hours at 27° C. Isolated colonies only 
should be studied. 
