288 BIOLOGY OF PNEUMOCOCCUS 



while the acetyl polysaccharide, under the conditions of the test, 

 exerted an inhibitory influence on sheep-cell hemolysis by the 

 A-antiserum up to a dilution of 1 to 1,000,000 of a one per cent 

 solution. Furthermore, the authors could demonstrate the activity 

 of the acetyl polysaccharide by complement fixation and by inhibi- 

 tion of group-specific iso-agglutination. 



Witebsky, Neter, and Sobotka reported another interesting ob- 

 servation on the properties of the acetyl polysaccharide. When 

 this substance was treated with the feces filtrate previously de- 

 scribed by Schiff and Akune, 1233 by Schiff and Weiler, 1234 later by 

 Witebsky and Satoh, 1527 and still more recently by Sievers, 1285 it 

 lost much of its inhibitory action toward the group-specific A-anti- 

 serum, and also its ability to inhibit the iso-agglutination of Group 

 A blood cells. Moreover, the acetyl polysaccharide of Type I Pneu- 

 mococcus, after having lost its reactivity toward the group-spe- 

 cific A-antiserum following treatment with feces filtrate, still re- 

 acted with Type I antipneumococcic serum that had previously 

 been absorbed with deacetylated Type I polysaccharide. 



Witebsky, Neter, and Sobotka, 1526 in the introduction to their 

 communication, mentioned the correlation between the Forssman 

 antigen and the blood-group specific substance of human blood- 

 group A. This fact, considered along with the relation existing be- 

 tween pneumococci and the blood-group specific substances A and 

 B as reported by Bailey and Shorb, 66 and the known carbohydrate 

 nature of the blood-group substance A as demonstrated by Land- 

 steiner, 780 Landsteiner and Levene, 781 and by Brahn, Schiff and 

 Weinmann, 146 and then the isolation by Freudenberg and Eichel 482 

 from the urine of men belonging to group A of a carbohydrate 

 closely resembling in its chemical structure the type-specific poly- 

 saccharide of Pneumococcus of Avery, Heidelberger, and Goebel, 

 reveals a field of investigation which yet remains to be explored. 



RECENT METHODS OF PREPARING CAPSULAR POLYSACCHARIDE 



The effect of alkali in impairing or destroying the antigenicity 

 of the specific polysaccharides of Pneumococcus was tested by Fel- 



