278 BIOLOGY OF PNEUMOCOCCUS 



groscopic, white, amorphous powder, soluble in the range pH 1 to 

 9, and containing no sulfur or phosphorus. Its elementary analysis, 

 amino nitrogen content, and specific rotation were practically 

 identical with the soluble specific substance as prepared by Heidel- 

 berger, Goebel, and Avery. 



The soundness of the reasoning was shown by the outcome of 

 precipitin tests with this new preparation of the A substance and 

 SSS. Both, in a dilution of 1 to 4,000,000, precipitated Type I 

 immune serum. When the serum was absorbed with soluble specific 

 substance, whereas SSS no longer gave a precipitate, the A sub- 

 stance produced a precipitate with the SSS-absorbed serum even 

 when added in a concentration of 1 to 4,000,000. On the other 

 hand, the A substance completely removed the precipitin for both 

 itself and the soluble specific substance. The authors had, by obvi- 

 ating the injurious effect of alkali on the carbohydrate, succeeded 

 in largely preserving the chemical and antigenic integrity of the 

 specific polysaccharide of Type I Pneumococcus, and had supplied 

 an explanation for one of the basic causes of the varied immuno- 

 logical behavior of the different carbohydrate preparations previ- 

 ously reported. 



RELATION OF THE ACETYL GROUP TO THE IMMUNOLOGICAL AC- 

 TIVITY OF PNEUMOCOCCUS 



The diversity of the several polysaccharides had also naturally 

 perplexed Avery and Goebel who, quite independently of Pappen- 

 heimer and Enders and while their wprk was in progress,* set 

 about the acquisition of a fuller knowledge of the nature of the 

 relationship existing between the specifically reacting derivatives 

 studied by other investigators and the type-specific polysaccharide 

 formerly described by Avery and his colleagues. In a communica- 

 tion published in 1933 Avery and Goebel 46 presented evidence that 

 they had isolated the soluble specific substance in a chemical form 



* The paper by Pappenheimer and Enders appeared in October, 1933, and 

 that by Avery and Goebel in December of the same year. 



