CHEMICAL CONSTITUENTS 



281 



ANALYSES OF THE ACETYL POLYSACCHARIDE OF PNEUMOCOCCUS 



TYPE I 



* Type I antipneumococcus serum previously absorbed with Preparation 2 A 

 (deacetylated). 



t This sample of deacetylated polysaccharide was obtained by alkaline hy- 

 drolysis of Preparation 2. This material is identical with the carbohydrate 

 formerly known as the soluble specific substance of Type I Pneumococcus. 



t An analysis of carbon and hydrogen was made on a sample of deacetylated 

 carbohydrate which had been reprecipitated five times at its isoelectric point. 

 The material contained no ash, and had a carbon content of 40.33 per cent and 

 a hydrogen content of 6.23 per cent. 



§ Unabsorbed Type I antipneumococcus serum. 



soluble specific substance as it probably exists in the pneumococ- 

 cal cell. This hypothesis is further strengthened by the antigenic 

 behavior of the acetylated polysaccharide when compared with 

 that of the intact pneumococcus and with that of the soluble spe- 

 cific substance as it is released from the cell during natural autoly- 

 sis. The experimental evidence presented by Avery and Goebel goes 

 a long way toward reconciling the conflicting differences in some of 

 the various carbohydrate derivatives isolated by other workers 

 from the pneumococcal cell and its products. 



The same authors found that both the acetyl polysaccharide and 

 the deacetylated polysaccharide were precipitated by homologous 

 immune serum in the highest dilution tested, representing a final 

 concentration of one part in three million. When, however, the se- 



