358 IMMUNOLOGY 



VIII, IX, XII, XXII, XXV, and XXVI. She reports amino 

 sugar (after hydrolysis) in Types I, IV, V, VII, IX, X, XII, XIII, 

 XIV, XV, XVI, XIX, XX, XXI, XXIV, XXV, XXVII, XXIX, 

 XXX, and XXXI. Types I, IV, V, XII and XXV contain the 

 largest amount of nitrogen (about 5%). Type I alone has an ap- 

 preciable amount of amino nitrogen (2%). Edwards, Hoagland 

 and Thompson say that in the case of the specific polysaccharides 

 of Types II, III and VIII the difference appears to be principally 

 one of stereochemistry. These polysaccharides are haptens (Type I 

 is definitely antigenic) coupled to protein common to all pneumo- 

 cocci. The combination forms a complete pneumococcus antigen 

 that is type specific. The type specificit.y is due to the polysac- 

 charide hapten. 



Finland and Curnen (1938) report an interesting discovery 

 concerning the specific carbohydrate of pneumococcus XIV. They 

 observed tliat liorse immune sorum for this type of pneumococcus 

 contained agglutinins for human red cells. According to Hoag- 

 land, Beeson and Goebel (1938) this substance resembles to a 

 great extent the group " A " substance from pig stomach. 



Difference Between Immune Serum from Horses and Rab- 

 bits. — Heidelberger and Kendall (1933) have also found that 

 partial hydrolytic products of Type III specific polysaccharide 

 can be quantitatively freed from unhydrolyzed polysaccharide. 

 They find that the fractions yield specific precipitates with Type 

 III antipneumococcus serum obtained from horses but fail to give 

 a precipitate with similar immune serum obtained from rabbits. 

 In their opinion Felton's studies on antibodies for the pneumococ- 

 cus may offer an explanation of this. Felton found that pneu- 

 mococcus antibodies obtained from horse serum are precipitated 

 with the water-insoluble fraction of the serum glol)ulin* whereas 

 rabbit antipneumococcus sera yield no precipitate on dilution. 



Possible Explanation of Inhibition Phenomenon. — They say 

 that ''The failure of the hapten fraction to form insoluble com- 

 pounds with rabbit antibody may be connected with the greater 

 tendency of rabbit globulin to remain in solution," They also 

 suggest that this may explain the inhibition phenomenon of Tjand- 

 steiner and van der Scheer. 



*J. Immunol. 21: 341, 1931. 



