STUDIES UPON AGGLUTINATION 46 



ACTION OF FORMALIN ON PSEUDO AGGLUTINATION IN THE CROSS 



AGGLUTINATION REACTION WITH DIFFERENT 



IMMUNE SERA (TABLE 4) 



In conducting cross agglutination tests with various immune 

 sera pseudo agglutination usually did not take place with forma- 

 lin. However, certain strams of baciUi showed marked agglu- 

 tination, as well as specific agglutination, without formalin. 



Bad. typhosum. Non-spontaneous agglutinating bacilli tested 

 with the formalin showed very marked prevention of pseudo 

 agglutination in these immune sera: Bad. paratyphosum A, 

 and B, in horse serum, and even better in Bad. dysenteriae Shiga 

 serum, but showed strong spontaneous agglutination without it. 



The serum of polyvalent dysentery (1:2000), with Bad. ty- 

 phosum had almost the same agglutinatmg reaction as the Bad. 

 dysenteriae group, both with or without formalin. Hence, we 

 may use the serum for identification of Bad. typhosum as well 

 as for the Bad. dysenteriae group. 



Bact. paralyphosxim A. Formalinized Bad. typhosum serum 

 ( 1:200), prevented pseudo agglutination entirely, with non- 

 spontaneous agglutinating strains, while showing strong pseudo 

 agglutination without formalin. 



In the Bad. paratyphosum B serum (1:50), with non-spon- 

 taneous agglutinating bacilli, both with or without formalia, 

 agglutination does not appear. This serum showed no tendency 

 to cause pseudo agglutination for Bad. paratyphosum. A. 



Polyvalent dysentery serum, has agglutinated Bad. paraty- 

 phosum A, in almost the same degree with and without formalin; 

 this serum seems to have a tendency to agglutinate this bacillus, 

 but in this experiment the sei-um was highly concentrated 

 1:100. This reaction does not compare with the agglutinating 

 reaction of Bad. typhosum or the Bact. dysenteriae group, when 

 a dilution of 1 : 2000 or more is used. 



Bact. dysenteriae Shiga serum (1:50), showed negative agglu- 

 tination, both with and without formalin; this serum has no 

 tendency to agglutinate with Bact. paratyphosum A. 



Normal horse serum (1:50), shows very weak agglutination 

 when using formalin, and stronger without it, but this serum 

 shows a tendency to agglutinate only Avith Bact. paratyphosum A. 



