364 IMMUNOLOGY 



Somewhat analogous findings have been reported, according to 

 Chase and Landsteiner, for *S^. paratyphi G and certain Pas- 

 tcurcllas. 



Shig-ella dysenteriae. — The antigenic complex of Shiga has 

 been studied by Morgan (1936, 1937, 1938). He reports that it 

 stimulates the production of both antibacterial and heterophile 

 antibodies and is thouglit to be the endotoxin of Shiga. Upon 

 fractionation he obtained in addition to the specific polysac- 

 charide, lipoidal and other material. The polysaccharide con- 

 tains 1.6 per cent nitrogen and yields 98 per cent reducing sugar 

 on hydrolysis. The antigenic substance then appears to be a carbo- 

 hydrate-lipid complex. 



V. cholerae. — Studies of cliolera vibrios has resulted in wliat 

 appears to ])c the establishment of six groups according to Mitra. 

 Two types were distinguished by differences in globulin fractions. 

 Landsteiner and Chase (1939) say that when these results are 

 considered together with three sorts of specific carbohydrates that 

 have been isolated it ''permits of the establishment of six groups 

 of vibrios." 



White (1937) studied the receptor complex of strains of 

 V. cholera found in India. He found the receptors to be 

 antigenic and located in the specific polysaccharide. He does not 

 assume that the antigenic factors causing multivalence represent 

 so many different substances. Instead he thinks of the multivalence 

 as due to the presence of individual receptor substances in the 

 polysaccharide molecules and to combinations of these functioning 

 as complex receptors. He postulates the existence of three 

 primary receptor groups in the cholera polysaccharide molecule. 



H. influenzae. — It was formerly thouglit that //. influenzae 

 organisms constituted a heterogenous group. Zinsser and Bayne- 

 Jones (1939) are of the opinion that the smooth H. influenzae 

 represent a homogenous group. It is only after dissociation into 

 "R" forms that they become serologically heterogeneous. Pitt- 

 man (1931) found that the ''S" forms produced a soluble specific 

 substance. Dingle and Fothergill have isolated this substance and 

 identified it as a carbohydrate. Serological tests with this sub- 

 stance gave positive precipitation in high titer with antisera ob- 

 tained from both horses and rabbits. While numerous cross re- 



