468 MICROBIOLOGY 



As can be seen from Table II, the final volume in each 

 tube is always uniformly 5 cc. Thus the different amounts of 

 the blood derivatives used are always made up to 5 cc. by 

 adding salt solution. 



After adding the substances to the test tubes in the order 

 given, the tubes are well shaken, placed in the test tube rack, 

 and put in an incubator at 37 C. for two hours. Then the 

 tubes are removed from the incubator and the results read.* 



The highest dilution in which complete hemolysis has 

 taken place represents the titre of the hemolytic amboceptor. 

 Thus if complete hemolysis has taken place up to and includ- 

 ing the tube where the dilution of the rabbit serum was 1-2000 

 (Tube No. 6, Table II), the hemolytic titre of this serum is 

 represented by 1-2000. This dilution, however, is not used in 

 the glanders test; but rather its double strength, which would 

 be 1-1000. The titre of the hemolytic amboceptor for use in 

 the diagnosis of glanders should not be less than 1-1000 and 

 therefore if the rabbit serum should prove to be of a lower 

 titre it should be discarded. It often happens that some rab- 

 bits are found to be unsuited for the production of amboceptor 

 and the titre of their serum can not be raised high enough 

 even after repeated inoculations with washed sheep corpuscles. 



It is advisable to preserve the hemolytic amboceptor in 

 small vials containing 1 to 2 cc. of the rabbit serum, and seal 

 the corks with paraffin or sealing wax. 



3. Complement. The complement which is contained in 

 the blood serum of a normal guinea pig is employed. The 

 complement should be titrated to determine its efficiency to 

 act with the hemolytic amboceptor. 



Titration of Complement. By titration of the comple- 

 ment there is aimed to be established a complement unit which 

 is the smallest quantity of complement necessary to produce 

 complete hemolysis in the presence of one amboceptor unit 



* If the tubes are placed in a water bath kept at 37 C. the time 

 here may be shortened to one half hour. 



