CROSS-AGGLUTINATION 



443 



The property of reciprocal agglutination was limited to the two 

 strains described. Other cultures of B. coli and B. dysenteriae 

 Shiga did not exhibit it. That is, agglutinating sera prepared 

 with the particular strains of the. colon and Shiga dysentery 

 bacilli mentioned reacted on each other quite as on their own 

 cultures, while other colon bacilli showed no especial agglutinating 

 capacity with the Shiga immune sermn nor did other Shiga bacilli, 

 with the colon agglutinating serum. Similarly the stock poly- 



TABLE 2 

 Absorption tests for agglutinins performed with homologous and heterologous cultures 



valent dysenteric horse serum agglutinated the particular B. 

 coli strain at 1 : 2000, which was its value to its homologous serum. 

 Single colonies of each organism were selected after several 

 platings and employed to immunize rabbits. The injections 

 were given at three day intervals. The rabbit receivmg the 

 culture of B. coli was given five intravenous injections, beginning 

 with 1/100 and ending with 1/10 of an agar slant of living cul- 

 ture. The rabbit receiving the culture of the Shiga bacillus 

 received seven intravenous injections, beginning with l/50th 



