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BACTERIOLOGY. 



corpuscular elements will sink to the bottom, leaving 

 the supernatant fluid quite clear. This may then be 

 pipetted oif, either into sterilized test-tubes, about 8 c.c. 

 to each tube, or into small sterilized flasks of about 100 

 c.c. capacity. It is then to be sterilized by the inter- 

 mittent method at low temperatures, viz., for one hour on 

 each of five consecutive days at a temperature of 

 68°-70° C. During the intervening days it is to be 

 kept at the room temperature to permit of the de- 

 velopment of any spores that may be present in their 

 vegetative forms, in which condition they are killed by 

 an hour's exposure to the temperature of 70° C. 



FlQ. 16. 



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



At the end of this time the serum in the tubes may 

 either be retained as fluid serum or solidified at between 

 76°-80° C. In solidifying the serum the tubes should 

 be placed in an inclined position so that as great 

 a surface as possible may be given to the serum. The 



