154 THE AGGLUTININS. 



rather than in the diagnosis of disease. They recommended that 

 large gainea-pigs should be immunized by intraperitoneal injections 

 of dead cultures, continued for from four to six weeks, until a high 

 degree of immunization should be secured, and that the peritoneal 

 lymph or blood serum of these animals might be used to determine 

 with certainty whether or not a suspected microorganism was the 

 vibrio of Asiatic cholera or the bacillus of typhoid fever. They 

 stated that if with such a serum from an animal immunized with the 

 cholera germ agglutination does not occur promptly and completely, 

 it can be said with certainty that the germ under suspicion is not 

 the vibrio of cholera, and the same test can be applied with equal 

 certainty in the detection of the typhoid bacillus. On the other 

 hand, if the reaction is positive, the identity of the microorganism 

 must still remain in doubt. We have carefully read the original 

 paper of Gruber and Durham, and we fail to find therein any reason 

 for believing that these investigators at that time had any idea that 

 the phenomenon which they were investigating was soon to become 

 one of the most certain and easily applicable methods for the diag- 

 nosis of typhoid fever. It is true that they speak of the serum test 

 as a diagnostic measure, but from the context it appears that by the 

 term diagnosis they mean the specific and positive identification of a 

 suspected bacterium. 



A few months after the publication of the last-mentioned contri- 

 bution, Widal * reported the successful application of the phenomenon 

 of agglutination in the diagnosis of typhoid fever, and among clini- 

 cians it is generally known as the "Widal reaction." 



Our scientific information concerning the agglutinins has been ob- 

 tained principally from the researches of Widal and Sicaixi,' Nicolle,' 

 and Winterberg.* 



It is quite evident that in such a reaction as that observed in ag- 

 glutination there must be two factors. One of these, which we may 

 designate the a^lutinin, is found in the serum ; while the other, 

 which may be denominated the agglutinable substance, is furnished 

 by the bacterial culture. The product which results from the reac- 

 tion between these bodies may be designated the agglutinate. We 

 will first give our attention to the agglutinins. The normal serum 

 of certain animals is capable of manifesting a slight agglutinating 

 action upon certain bacteria, notably the colon bacillus and the ba- 

 cillus of Eberth. The normal serum of the horse, donkey, dog, and 

 rabbit, when added to cultures of the Eberth bacillus without dilu- 

 tion causes agglutination. Indeed, the serum of these animals may 

 agglutinate the typhoid bacillus when diluted 1 to 30. The nor- 

 mal serum of the guinea-pig has no agglutinative action on tliis or- 



' SocUti MedieaU de» Hospitava, June 26, 1896. 

 ' Annalea de V Institut Pasteur, 11, 

 ' Anjiales de V Institut Pasteur, 8. 

 * Zeits. fur Sygiene, 32. 



