356 IMMUNOLOGY 



Anderson (1932) and also Smedley-MacLean (1932) have re- 

 viewed the work of Anderson (1930, 1931), Sabin and Doan 

 (1927) and of Doan (1929) on the fatty acids and phosphatids 

 isohited by Anderson from the members of the acid-fast group. 

 Anderson (1940) has extended his work on lipids of the tubercle 

 bacillus. He reports that two polysaccharide fractions isolated 

 from two preparations of phosphatids gave different cleavage 

 products. 



Tuberculo-Phosphatids and Fatty Acids.- — The tuberculo- 

 phosphatids differ from phosphatids obtained from other sources 

 in their phosphorus and nitrogen content. According to Anderson 

 they also contain a large percentage of what appears to be a new 

 type of polysaccharide. On hydrolysis the latter yields mainly 

 mannose and inosite. Pangborn and Anderson (1933) and 

 Anderson and Newman (1933) have also reported on the isola- 

 tion of trehalose from the timothy and tubercle bacilli, respec- 

 tively. 



Immuno-Chemical Studies of the Pneumococcus. — Another spe- 

 cies of bacteria that has been both extensively and intensively stud- 

 ied from the standpoint of immunochemistry is the pneumococcus. 

 Attention has already been called to the early discovery of Dochez 

 and Avery (1917), Zinsser (1921), Zinsser and Parker (1923), of 

 soluble specific substances from pneumococci that are type specific 

 in that they give specific precipitates or positive complement fixa- 

 tion when mixed with their respective immune sera. These sub- 

 stances have been carefully investigated by Heidelberger, Goebel, 

 and Avery* since 1923. Their results may be briefly summarized 

 as follows : 



Properties of Type Specific Polysaccharides. — In the begin- 

 ning they found that all three types of specific soluble substances 

 are polysaccharides quite dissimilar chemically as well as immuno- 

 logically. Unfortunately they employed methods at first which 

 deacetylated the natural soluble specific substance. In view of 

 the observations of Schiemann and Casper (1927), Saito and 

 Ulrich (1928), Enders (1930) and Wadsworth and Brown (1931) 

 that pneumococci contain an antigenic polysaccharide, Avery and 



*Heidelberger, Goebel, and Avery: J. Exper. Med. 38: 73, 1923. 



