390 HEMOLYSINS 



bacteriolysis one, the thermostabile amboceptor present in the immune 

 serum, and the second, thermolabile alexin or complement, furnished 

 by the peritoneal exudate in the Pfeiffer test, or by any fresh normal 

 serum in the test-tube bacteriolytic reaction. The discovery and study 

 of the specific serum hemolysins aided greatly in a better understanding 

 of bacteriolysis and cytolysis in general. 



Specificity of Hemolysins. The hemolysins are highly specific anti- 

 bodies, and although partial or group hemolysins may be formed and 

 act upon the corpuscles of closely related species, as antihuman hemolysin 

 on the corpuscles of the higher apes, yet the main hemolysin may be so 

 potent that high dilution of the immune serum practically rules out the 

 activities of group hemolysins, the hemolytic amboceptor proving highly 

 specific for the alien corpuscles responsible for its production. 



NORMAL HEMOLYSINS 



Just as small amounts of antitoxins, agglutinins, and opsonins may 

 be found in normal serums, so, also, normal hemolysins may be present. 

 Their most important practical significance is concerned with comple- 

 ment-fixation reactions, where a close and intimate quantitative rela- 

 tion exists between the complement and hemolytic amboceptor used. 

 As an excess of hemolytic amboceptor may produce hemolysis with a 

 decreased amount of complement, in a given test for free complement, as 

 in Wassermann's syphilis reaction, the patient's serum may contain so 

 much natural antisheep amboceptor as to make up for slight binding of 

 complement and give undue hemolysis or even a false negative result. 



Hemolysis of alien corpuscles by a normal serum is found to depend 

 upon the same mechanism of amboceptor and complement as in the ar- 

 tificial immune serums. The amboceptors are easily removed by adding 

 the corresponding corpuscles to the cold serum and centrif uging the mix- 

 ture after allowing it to stand at 0-5 C. for an hour or two. The su- 

 pernatant fluid will now be found to be free from amboceptors, whereas 

 by adding a little normal complement serum to the corpuscles hemolysis 

 results, indicating that the amboceptors had been bound to these. If a 

 normal serum contains several different amboceptors for as many dif- 

 ferent bloods, all may be removed at the one time by adding the respec- 

 tive corpuscles to the serum and allowing sufficient time to elapse for 

 the amboceptors to become linked to their corpuscles. 



Normal serum, therefore, probably contains numerous antibodies of 

 the amboceptor type, adapted to dissolve various foreign substances 



