282 BIOLOGY OF PNEUMOCOCCUS 



rum was absorbed with the deacetylated polysaccharide, after re- 

 moval of all precipitins for this form of the specific carbohydrate, 

 the serum still reacted with the acetyl polysaccharide in equally 

 high dilution. On the other hand, after absorption with the acetyl 

 polysaccharide, the serum was completely exhausted of all precipi- 

 tins for both forms of the carbohydrate, as shown by the absence 

 of reaction when tested with each substance in dilutions ranging 

 from 1 to 20,000 to 1 to 3,000,000. The deacetylated polysaccha- 

 ride, therefore, selectively removed from the serum only the pre- 

 cipitins for itself, whereas the acetyl polysaccharide completely 

 removed all the precipitating antibodies for both forms of the spe- 

 cific substance. 



Avery and Goebel discussed these results by saying: 



The specific precipitation of the acetyl polysaccharide in serum pre- 

 viously absorbed with the deacetylated carbohydrate, and the readiness 

 with which the former substance is converted into the latter by heat, are 

 similar to the relationships observed by Enders, and by Wadsworth and 

 Brown, between the substances isolated by them and the soluble specific 

 substance which they prepared according to methods previously de- 

 scribed in this laboratory. Since the specific substance thus prepared is 

 now known to be the deacetylated polysaccharide, it seems not improb- 

 able that the differences they observed, like those noted in Table II, 

 represent the reactions not of two different carbohydrates but of a sin- 

 gle substance in two chemically different forms ; namely, the naturally 

 acetylated and the artificially deacetylated polysaccharide. 



Avery and Goebel also found that after absorbing Type I anti- 

 pneumococcic serum separately with acetyl and deacetylated Type 

 I polysaccharides, the serum absorbed with the former carbohy- 

 drate no longer agglutinated Type I pneumococci, while immune 

 serum treated with the latter substance still contained specific ag- 

 glutinins. The authors next tested the ability of the acetyl and the 

 deacetylated polysaccharides to absorb the protective antibodies 

 from specific immune serum and discovered that while the deacety- 

 lated carbohydrate reduced the titer of protective antibodies, it 

 failed to remove them all, since the serum, absorbed by this sub- 



