HEMAGGLUTININS 115 



up to 1:3000 by the addition of 0.5 per cent, phenol in normal saline, and kept for 

 twenty-four hours in the incubator. 



A somewhat simpler procedure is to dilute new tuberculin B. E. to i: 100 with 0.5 

 per cent, of carbolic saline solution, centrifugalize this for six minutes and then dilute 

 to i : 1000. The solution thus obtained can be preserved in the ice-box for fourteen 

 days. Just before using, a still further dilution of i : 10 is made. 



The agglutination test has not been generally adopted as a method of diagnosis. 

 The technique is rather difficult, and the results not absolutely reliable. The reason 

 for this is that high agglutination values are rarely met with, and slight ones 

 are found even in normal individuals. Then, too, the methods of tuberculin diagnosis 

 are so much simpler that they have been given the preference. 



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 tuber- 

 culosis 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 intra- 

 venous 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 tritu- 

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

 measuring glass so that 40 to 50 c.cm. of carbolic-saline solution are added for each 

 culture. The entire mixture is filtered through paper and 3 c.cm. are used in each test. 

 Normally, horses may have an agglutination titer up to 1 1400. Glanders in- 

 fected animals react as high as i : 2000. Injections of mallein increase the agglutina- 

 tion titer. Experiences in this respect with the human being are still scanty. 



Hemagglu- J ust as injections of bacteria produce bacterial agglutinins, 

 tinins, injections of erythrocytes stimulate the formation of hem- 

 Immune and agglutinins which cause the red blood cells to congregate in 

 Normal. c l umps . 



At times the presence of hemagglutinins is masked by the 

 simultaneous existence of hemolysins which dissolve the red blood corpus- 

 cles. If, however, the immune serum is heated to 56* C. the complement 

 is destroyed, thus interfering with the action of the hemolysin and 

 allowing the agglutinins to exhibit their action. In other instances as 

 during the immunization of rabbits with dog's erythrocytes, hemagglu- 

 tinins are formed in such great quantities that by 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 hemolysis can be demonstrated only if clumping is prevented 

 mechanically, by thorough shaking of the mixture. 



Also under normal circumstances, i. e., without immunization, the serum 

 of one animal species can to a certain degree agglutinate (and hemolyze) 

 the red blood cells of another species. The quantity of these normal 

 hemagglutinins is comparatively small. 



