HEMAGGLUTININ. 107 



Koch himself advised the agglutination test, not as a means of diagnosis, but rather 

 as an aid in tuberculin therapy. He found that during the treatment of tuberculosis 

 with new tuberculin the agglutinative power of the patient's serum increased. He 

 therefore took this as an index of the acquired immunity. Further study, however, 

 convinced him that the agglutination cannot thus be interpreted, so that at the present 

 day tuberculosis agglutination has no practical application. 



10. Glanders. Highly valent sera can be obtained, according to Kleine, by intravenous 

 immunization of donkeys and goats. The serum serves for identification of the glanders 

 bacilli. Kleine prepares a standard bacterial emulsion in the following manner: Four 

 well grown glanders cultures are killed at 60 C. and the mass of bacteria triturated in 

 2 c.c. of 1/2 per cent, carbolic-saline solution. This is then diluted in a measuring glass 

 so that 40 to 50 c.c. of carbolic-saline solution are added for each culture. The entire 

 mixture is filtered through paper and 3 c.c. are used in each test-tube. Normally, horses 

 may have an agglutination titer up to i : 400. Glanders infected animals react as high as 

 i : 2000. Injections of mallein increase the agglutination titer. Experiences in this 

 respect with the human being are still scanty. 



Just as injections of bacteria produce bacterial agglutinins, 



Hemagglu- injections of erythrocytes stimulate the formation of hem- 



tinin. agglutinins which cause the red blood cells to congregate in 



clumps. 



At times the presence of hemagglutinins is masked by the simultaneous 

 existence of hemolysins which dissolve the red blood corpuscles. If, however, 

 the immune serum is heated to 56 C. the hemolysin is destroyed, thus allow- 

 ing the agglutinins to exhibit their action. In other instances as during the 

 immunization of rabbits with dog's erythrocytes, hemagglutinins are formed 

 in such great quantities that in mixing the immune rabbit's serum with the 

 dog's erythrocytes so strong an agglutination occurs that the hemolysins can 

 no longer attack the clumped erythrocytes. The hemolysin presence can 

 be demonstrated only if clumping is prevented mechanically, by thorough 

 shaking of the mixture. 



