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LOEFFLER'S BLOOD SERUM. 



This medium consists of 3 parts blood serum and 

 i part of i per cent broth with reaction +0.8. The 

 serum is obtained from fresh beeves' blood, which is col- 

 lected in sterile jars and allowed to stand for twenty-four 

 hours in the refrigerator for coagulation. The serum 

 is then drawn off, filtered, and mixed with the dextrose 

 broth in the proportion above indicated. Hill finds that 

 filtering the serum through the coagulum obtained after 

 adjusting the reaction of the broth gives a filtrate which 

 is clear and almost colorless (Hill, 1899). 



Tubes are filled with the mixture, placed in trays so 

 that the desired slant is obtained, and carefully heated 

 in a Koch coagulator containing cold water in the water- 

 jacket. This water is brought to a boil and kept boiling 

 for three hours. Repeating this process on three suc- 

 cessive days solidifies the serum so that it may be subse- 

 quently sterilized in flowing steam for twenty minutes 

 on three successive days. 



PHENOL BROTH. 



To 1000 c.c. water add separately, and in the following 

 order, 100 grams dextrose, 50 grams peptone, 2.5 grams 

 phenol. Heat until all constituents are dissolved, boil 

 for fifteen minutes, and sterilize for fifteen minutes at 

 110-120 C. 



