BLOOD SERUM MEDIA 55 



The prepared tubes are placed in the incubator at 37 C , and 

 the non-sterile tubes placed on one side. (This medium is specially 

 adapted for the gonococcus and Influenza bacillus.) 



XCVIII. AGAR-AGAR GELATINE. 



This medium is prepared in the same way as ordinary agar-agar, 

 ( 93), using 1-5 grammes of agar-agar, and when it is dissolved 

 adding 50 grammes of gelatine. 



BLOOD SERUM MEDIA. 



XCIX. FLUID BLOOD SERUM. 



1. Collect the blood from a living animal into a large sterile glass 

 jar, under sterile precautions, and close it tightly. 



2. Place the jar in an ice-chest for twenty -four hours. 



3. Remove the serum into tubes with a sterile pipette. 



4. Place the tubes of serum in the incubator at 37 C. 



5. Remove any tubes that become turbid. 



C. SOLID BLOOD SERUM. 



1. Collect the blood the same as in No. 1 process for fluid blood 

 serum. 



2. About fifteen minutes after it has begun to clot, pass a sterilized 

 glass rod between the clot and the wall of the jar, breaking up the 

 adhesions that prevent the clot from sinking. 



3. Close the jar tightly, and place in an ice-chest twenty-four to 

 forty-eight hours. 



4. Draw off the serum with sterilized pipettes into sterilized tubes, 

 and close with sterilized cotton wool plugs. (This is the only medium 

 where the tubes and plugs are sterilized before filling. ) 



5. Place the tubes in a blood serum sterilizer, and heat to 65 or 

 68 C. for one hour on each of five successive days, and place in the 

 incubator at 37 C. for several days to test whether they are sterile. 



6. Place the sterile tubes in Koch's apparatus for solidifying blood 

 serum (see Fig. 10, p. 56), and heat to 75 or 80 C. until the serum is 

 solidified. 



