124 IMMUNE SERA 



greater the range, the better in general, is the 

 antigen. 



MAKING THE TEST. 



The order in which the various reagents are added 

 is as follows: Patient's serum, antigen, complement, 

 normal saline to equalize the amounts of fluid. The 

 tests are then kept at 37 C. in the incubator for 

 one hour or in the ice chest at about 8 C. for four 

 hours. It will be found that about 10 per cent 

 more positives will be obtained if the tests are kept 

 in the ice box than will be the case if they are incu- 

 bated at 37 C. The amount of sheep cells neces- 

 sary are sensitized by the addition of 3 units of 

 amboceptor to each o.i cc. of cells. These two 

 reagents may then be added to the tubes in one 

 operation. 



After the addition of sensitized cells the tubes are 

 placed in the water bath at 37 C. for haemolysis to 

 take place. The results are read as soon as the 

 antigen controls and the serum controls are com- 

 pletely haemolyzed. If the patient's serum in the 

 tubes which contain no antigen interferes with the 

 complete haemolysis of the sheep cells it cannot be 

 tested. If for any reason the antigen controls fail 

 to haemolyze, the tests made with this antigen must 

 be repeated. 



Complete haemolysis in all tubes indicates a 

 negative reaction. No haemolysis in any of the 



