362 IMMUNOLOGY 



until 1924-25 Avhen Mueller, Smith and Litarczek reported that 

 the polysaccharide thus obtained caused specific precipitation of 

 homologous immune serum. 



Heidelberger, Goebel and Avery (1925) found that the poly- 

 saccharide from strain E (Type B of Julianelle) is chemically 

 and imniunoloo'ically similar to but not identical with the soluble 

 specific substance of Type II pneumococcus. They found tliat im- 

 mune serum for strain E of Friedlander 's bacillus agglutinates 

 both the homologous organism and also Type II pneumococcus 

 and conversely immune serum for the latter agglutinates both 

 organisms. Similar results were obtained using the respective 

 polysaccharides and corresponding immune sera. When ab- 

 sorption experiments were carried out, however, it was found 

 that when Friedlander (strain E) immune serum was absorbed 

 with Type II pneumococcus, the agglutinins for the pneumococcus 

 were removed, but there remained agglutinins for the homologous 

 organisms; and likewise when pneumococcus Type II serum was 

 absorbed with Friedlander 's bacillus (strain E) the aggkitinins 

 for the latter were removed, but there remained agglutinins for 

 Type II pneumococcus. When either immune serum was absorbed 

 with its homologous organism, agglutinins for both were removed. 

 Similar results were obtained using the respective polysaccharides 

 and immune sera. 



It is interesting to note that Julianelle (1926) found im- 

 munological types to exist among forty strains of Friedlander 's 

 bacillus studied. These strains fall into three specific types which 

 he designates as A, B, and C and a heterogeneous one which he 

 has named Type X. The strain whose capsular substance is similar 

 to that of pneumococcus Type II corresponds to Type B of 

 Julianelle. 



The soluble specific substances of Types A and C have been 

 studied extensively by Goebel (1927) and Goebel and Avery 

 (1927). The former investigated the hydrolytic products of Type 

 A polysaccharide and found that it yielded on hydrolysis an 

 aldobionic acid, glucose, and a second acid not identified. These 

 three compounds were found to be present in the ratio of 1 :1 :1. 

 Goebel found that the new aldobionic acid consists of a molecule 

 of glucuronic acid linked to a molecule of glucose through its re- 

 ducing group. It is iso7neric with an acid derived from the soluble 



