BACTERIAL ANTIGENS AND SPECIFICITY 357 



Goebel (1933) reinvestigated the type specific polysaccliaride of 

 Type I and came to the following conclusions: 



1. The soluble specific substance of Type I is an acetyl poly- 

 saccharide. 



2. The methods they employed in 1923 in isolating Type I SSS 

 resulted in deacetylating the natural acetyl polysaccharide. 



3. The acetyl polysaccharide is antigenic in that the injection 

 of it into mice leads to the development of an immunity to Type I 

 pneumococcus but not to the formation of precipitins. Zinsser and 

 Bayne- Jones (1934) speak of this as a functional immunity, 



4. The acetyl polysaccharide is quite soluble in water. 



5. It shows a specific optical rotation in aqueous solution of 

 +270. 



6. It has a nitrogen content of 4.8 i^er cent. When treated witli 

 nitrous acid in the cold, about 45 per cent of the nitrogen is li1)- 

 erated in the amino form. 



7. It yields reducing substances when h^^lrolized willi dilute 

 mineral acids. When the reducing substance appears, the sero- 

 logical specificity is lost. 



8. The type-specific polysaccharide is also soluble in 80 per cent 

 acetic acid. 



9. Dilute aqueous solutions (0.5 per cent) are precipitated by 

 silver nitrate, neutral and basic lead acetate and phosphotungstic 

 acid. It is incompletely precipitated by barium hydroxide. It is 

 precipitated by tannic acid but not by uranyl nitrate. 



10. The ninhydrin, biuret, picric acid and sulphosalicylic acid 

 tests are negative. 



11. Neither phosphorus nor sulphur was detectable in highly 

 purified preparations of the acetyl polysaccharide. 



Marrack (1938) describes Type I polysaccharide as containing 

 a basic group and a trisaccharide with two uronic acid molecules 

 and amino sugar. 



Brown (1939) has summarized in tabular form the chemical 

 data on the soluble specific substances of Types I to XXXII pneu- 

 mococci. Apparently they all contain dextrose although only 

 Types V, XI, and XXXII will reduce Fehling's solution before 

 hydrolysis. Types II, III and VIII are thought to be composed 

 of dextrose and aldobionic acid in a carbohydrate chain. Accord- 

 ing to Brown's data uronic acid was present in Types I, II, III, 



