BLOOD-SERUM 



121 



method suggested by Councilman and Mallory is now 

 generally used. It is as follows: Place the test-tubes con- 

 taining the serum in a slanting position in a dry air sterilizer 

 and heat them to from 80-90 C. for a time necessary 

 to solidify the serum. After this they are kept for twenty 

 minutes on three successive days in the steam sterilizer at 

 100 C. They should be kept at room temperature between 



FIG 19 



Chamber for sterilizing and solidifying blood-serum. (Koch.) 



the exposures to the steam. After this treatment the serum 

 should be sterile. 



Serum thus prepared may be kept from drying by burning 

 off in the gas flame the excess of cotton protruding from the 

 ends of the tubes and then forcing down upon the cotton 

 plugs clean, new, corks that have been sterilized by steam 

 under pressure. (Ghriskey.) 



To secure satisfactory results by this method several 



