112 BA CTERIOL OGY. 



the manufacture of antitoxins and other biological pro- 

 ducts. This serum, obtained under aseptic precautions, 

 has obviously an advantage, and has in our hands proven 

 entirely satisfactory for routine work. 



In either case the serum is to be decanted into clean, 

 sterile test tubes provided with cotton plugs, after which 

 it must be immediately sterilized. For this purpose the 

 method suggested by Councilman and Mallory is now 

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



FIG. 19 



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



containing the serum in a slanting position in a dry air 

 sterilizer and heat them to from 80 to 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 the exposures to the 

 steam. After this treatment the serum should be sterile. 

 Serum thus prepared may be kept from drying by 



