STORAGE OF H^EMOLYSIN 33! 



haemolytic doses per cubic centimetre. Such a serum 

 is strong enough for experimental work; indeed, for 

 many purposes, complete haemolysis down to tube 6 

 will indicate a serum sufficiently strong ( = 100 m. h. d. 

 per cubic centimetre) . If, however, only the first one 

 or two tubes are completely haemolysed, this is an 

 indication that the rabbit should receive further in- 

 jections in order to raise the haemolytic power to a 

 sufficiently high level. 



STORAGE OF H^EMOLYSIN. 



If, and when the haemolysin content of the rabbit's 

 serum is found to be sufficient, destroy the animal by 

 chloroform vapour. 



Remove as much of its blood as possible from the 

 heart under aseptic precautions into sterilized centri- 

 fuge tubes. 



Transfer the tubes of blood to the incubator at 

 37 C. for two hours then centrifugalize thoroughly. 



Pipette off the clear serum, and fill in quantities of 

 i c.c., into small glass ampoules or pipettes, and her- 

 metically seal in the blow-pipe flame, care being taken 

 to avoid scorching the serum. 



Place the ampoules when filled with serum and sealed, 

 in a water-bath at 56 C. for 30 minutes. This destroys 

 the complement, i. e., inactivates the serum, and at the 

 same time, provided the various operations have been 

 carried out under aseptic precautions, ensures its 

 sterility. A longer exposure reduces the haemolytic 

 power. 



Place the ampoules in a closed metal box and store 

 in the ice chest for future use. 



