SPECIFIC BACTERIAL PRODUCTS 447 



have been availed of in both diagnosis and therapeutics. The 

 more important of these are agglutinins, precipitins and op- 

 sonins. 



Agglutinins.* Agglutinins are substances produced in 

 the body by the stimulation of the cells by certain agents 

 known as agglutinogens. These are cultures of living bacteria, 

 heated or killed cultures and in some cases culture filtrates. 

 They may be introduced subcutaneously, intravenously or into 

 the abdominal cavity. It has been shown that certain animal 

 tissues like red blood corpuscles seem to cause the production of 

 agglutinins specific for the injected corpuscles. The agglu- 

 tinins are present to a limited degree in the normal serum. 

 These are known as the "normal agglutinins" but they seem 

 to have the same nature as the immune agglutinins. It is 

 possible that their presence in normal serum is traceable to the 

 action of certain parasitic bacteria. 13 



The action of the agglutinins is specific in that they clump 

 the bacteria (agglutinogens) which cause their production. 

 Thus the serum of a glandered horse will clump the free glan- 

 ders organisms when suspended in physiological salt solution or 



* The first observations on agglutination were made by Gruber 

 and Durham (Munisch. Med. Woch., Bd. XLIII (1896) p. 285). Later 

 'Charrin and Roger (Compt. rendu de la Soc. de Biol., Vol. I 9 serie 

 (1889) p. 667) in experiments made with Pseudomonas pyocyaneus 

 observed the clusters of bacteria which settled to the bottom of the 

 fluid. A number of other workers observed the clumping of bacteria 

 when brought in contact with immune sera. Widal (Soc. Med. des 

 Hopitaux, 1896) showed that the agglutination had an important 

 application in diagnosis. He applied it to typhoid fever, and the 

 method is now known as the Widal or the Gruber-Widal test. The 

 same principle was applied by M'Padyean (Jour. Comp. Path, and 

 Therap., Vol. IX (1896) p. 322), Bonome (Centralbl. f. Bakt., Bd. 



XXXVIII (1905) p. 601), Kleine (Zeit. f. Hyg., Bd. XLIV (1903) p. 

 183), Schiitz and Miessner (Arch. f. wiss. u. prak. Tierheilk., Bd. 

 XXXI (1905) p. 353), and Schnurer (Centralbl. f. Bakt, Bd. 



XXXIX (1905) p. 180) in the diagnosis of glanders, the first WOFK 

 being done by M'Fadyean. (See diagnosis of glanders). The litera- 

 ture on the subject of agglutination as a means of diagnosis is ex- 

 tensive. 



"Hoffman. Hyg. Rundschau, Bd. XIII (1903) p. 114. 



