168 MODERN BIOLOGIC THERAPEUSIS 



fluid is decanted and a sufficient amount of fresh 

 saline solution is added to make a moderately 

 opaque solution. The suspension is now ready 

 to be used. 



Bacterial Suspension The bacteria are 

 grown upon a suitable solid medium and, at the 

 height of their growth, are washed off with a 

 sufficient amount of 0.85 per cent sodium chlor- 

 ide solution to make a moderately opaque 

 emulsion. 



CARRYING OUT THE TEST 



Into special glass tubes are placed, by means 

 of pipets, definite quantities of the serum to 

 be tested and the bacterial suspension. Into 

 other tubes are placed definite quantities of 

 normal serum and the bacterial suspension. The 

 tubes are then incubated for one hour in a water 

 bath. This is to enable the opsonins, in the 

 serum being tested, to prepare or sensitize the 

 bacteria in such a way that they will later be 

 more readily taken up by the leukocytes. At 

 the end of the hour, definite quantities of the 

 leukocytic suspension are added to all of the 

 tubes, which are then returned to the water bath 

 for one-half hour. During this incubation, the 



