ROLE OF AGGLUTININS IN IMMUNITY 289 



doubtful or negative. There is no satisfactory explanation for" this 

 variation, mixed infection, intestinal hemorrhage, etc., being regarded 

 by some as responsible for it. 



Conglutination. In 1906 Bordet and Gay 1 described a colloidal 

 substance in beef serum heated to 56 C. which. has the property of caus- 

 ing a characteristic clumping and increased lysis of red blood-cells when 

 treated with a heated specific hemolytic serum and fresh alexin (com- 

 plement). Bordet and Streng, 2 in later studies on this substance, gave 

 to it the name "conglutinin." Streng 3 continued these studies with 

 bacteria and found that a typical clumping was produced by the mixture 

 of bacteria, fresh complement, conglutinin, and a specific immune serum 

 from which the agglutinins had been removed by absorption. By dia- 

 lyzing the beef serum the conglutinin was shown to be present in the 

 globulin fraction, and the reaction took place as well with bacteria 

 killed by heat or 0.1 per cent, liquor formaldehydi as with live organisms. 



In a study of dysentery in infants, Lucas, Fitzgerald and Schorer 4 first 

 applied this reaction to clinical diagnosis. They found it more sensitive 

 and specific than either the agglutination or fixation test. 



In their work cultures of the Flexner and Shiga dysentery bacilli 

 treated with 0.1 per cent, liquor formaldehydi were used. They con- 

 clude that in the conglutination test we have a means of diagnosis far 

 superior to any other form. 



Swift and Thro 5 did not find the conglutination reaction of much 

 greater value in the differentiation of various strains of streptococci than 

 the agglutination reaction. 



The technic of this reaction is given on page 307. 



R&le of Agglutinins in Immunity. The agglutinins were formerly 

 regarded as possessing a true protective and curative power. It has 

 .previously been mentioned that bacteria may be grown in a specific 

 agglutinating serum, and cultures made of agglutinated bacteria show 

 them to be fully alive and as virulent as before agglutination took place. 

 In certain cases agglutinins for a microorganism may be entirely absent, 

 and yet the animal enjoy an immunity. Bacteria that have been acted 

 upon by an agglutinin are apparently not altered in appearance, viabil- 

 ity, or virulence. 



Many observations tend to show that the agglutinating power of a 



1 Am. de 1'Inst. Pasteur, 1906, xx, 467. 



2 Centralb. f. Bakteriol., 1909, xlix, 260. 



3 Centralb. f. Bakteriol., 1909, 1, 47. 



4 Jour. Amer. Med. Assoc., 1910, Ivi, 441. 



6 Archiv. Int. Med., 1911, 7, 24. 

 19 



