280 BIOLOGY OF PNEUMOCOCCUS 



4.85 per cent of nitrogen, approximately one-half of which was 

 liberated in the amino form when the substance was treated with 

 nitrous acid in the cold. It did not reduce Fehling's solution until 

 after hydrolysis with dilute mineral acids. At the same time that 

 reducing sugars appeared in the solution, the serological speci- 

 ficity of the acetyl polysaccharide was destroyed. In this respect 

 its behavior was identical with that of the deacetylated polysac- 

 charide. 



The acetylated carbohydrate evidently contained uronic acids. 

 It was soluble in water and in 80 per cent acetic acid. Aqueous 

 solutions were precipitated by phosphotungstic acid, silver nitrate, 

 and neutral and basic lead acetate, and were incompletely precipi- 

 tated by barium hydroxide. Unlike the deacetylated product, the 

 acetyl polysaccharide was precipitated by tannic acid but not by 

 uranyl nitrate. It gave no color reaction with iodine-potassium 

 iodide solution. It did not immediately decolorize weak solutions of 

 potassium permanganate, and it gave negative reactions to the 

 biuret, ninhydrin, sulfosalicylic, and picric acid tests. No traces of 

 phosphorus or sulfur were detectable in the most highly purified 

 preparations of the specific acetyl polysaccharide. 



The table on page 281, copied from the article by Avery and 

 Goebel, shows the results of the analyses of the acetyl polysaccha- 

 ride of Pneumococcus Type I. 



The analytical data presented in the table show that the de- 

 acetylated product (Preparation 2 A), obtained by alkaline hy- 

 drolysis of the acetyl polysaccharide (Preparation 2), contained 

 no acetyl groups and was in all respects chemically identical with 

 the polysaccharide that had hitherto been known as the soluble 

 specific substance. This result agrees with that of Heidelberger and 

 Kendall 617 who previously had found that the Type I polysaccha- 

 ride (deacetylated) contained no acetyl groups. 



The results of the analysis corresponded closely with the calcu- 

 lated composition of the acetylated polysaccharide, and this sub- 

 stance, therefore, approached in its chemical make-up that of the 



