CHEMICAL CONSTITUENTS 257 



with Goebel and Avery 1410 continued the study of the newly iso- 

 lated fraction. The fraction was further purified by making the 

 solution (the water-clear supernatant fluid described above) alka- 

 line with sodium hydroxide and by precipitation with alcohol. The 

 material was dissolved in water and again reprecipitated from 

 faintly acid solution by alcohol. The procedure was repeated sev- 

 eral times. The final precipitate was washed with alcohol and ether 

 and freed from chlorides and was soluble in water but insoluble in 

 organic solvents. The substance in solution showed a specific rota- 

 tion of +25.0°, contained 5.07 per cent of nitrogen, and yielded 

 30.0 per cent of reducing sugars on hydrolysis. Unlike the type- 

 specific polysaccharide of Type I Pneumococcus it contained no 

 amino nitrogen, but like other pneumococcal carbohydrates was 

 protein-free. Tillett, Goebel, and Avery also made similar prepara- 

 tions from S strains of Type II and Type III pneumococci. 



The C Fraction was non-toxic for mice in amounts up to one 

 milligram, it produced no purpura, and an intravenous injection 

 of three cubic centimeters of a concentrated solution elicited no 

 symptoms in rabbits. Three series of seven daily injections of one 

 cubic centimeter of the concentrate, with weekly rests, failed to 

 produce in rabbits any precipitins for the C substance. When 

 mixed with antipneumococcic horse serum of Types I, II, and III 

 the somatic carbohydrate precipitated each of the three, thus ex- 

 hibiting a broad species coverage but no type-specificity. Tillett, 

 Goebel, and Avery concluded from chemical studies and animal ex- 

 periments that Fraction C was a common constituent of all pneu- 

 mococci, and that it was distinct from the specific polysaccharide 

 and the so-called nucleoprotein. 



The isolation of the C Fraction was also accomplished by Hei- 

 delberger and Kendall (1931 ) 617 during an investigation of the 

 polysaccharides of Type (not Group) IV Pneumococcus. They also 

 obtained the C substance from Type I and Type III pneumococci. 

 The preparations showed a higher optical rotation, higher nitro- 

 gen, and in two cases a higher reducing-sugar content on hydroly- 



