PRODUCTION OF ANTIPNEUMOCOCCIC SERUM 551 



mococcal antibody. The amount of precipitate obtained did not al- 

 ways parallel the protective titer of the antibody solutions. The 

 optimal yield of precipitate varied with dilution and the serologi- 

 cal type of the serum used. Thus dilutions of 1 to 18 and 1 to 20 

 for Type I, 1 to 14 and 1 to 18 for Type II, and 1 to 12 and 1 to 

 14 for Type III serum were recommended as yielding maxima of 

 antibody. The amounts thrown down were, however, also depend- 

 ent upon the hydrogen ion concentration of the water-serum mix- 

 ture, and zones of pH 5.5 to 7.8, 5.5 to 7.8, and 6.2 to 7.8 were 

 observed for serum of Types I, II, and III respectively. 



Banzhaf 70 corroborated Felton's observations on Type I serum 

 diluted tenfold with water containing phosphoric acid, and ob- 

 tained varying results with Type II and III serum similarly 

 treated. In 1928, Felton 403 published a further description of the 

 characters of the water-insoluble fraction of antipneumococcic se- 

 rum, and believed that the fraction, while similar in qualities to 

 pseudoglobulin, more closely resembled euglobulin. 



Felton's work received further confirmation in the experiments 

 of Savino, Negrete, and Acuna. 1221 Reiner and Reiner, 1133 using a 

 similar method of concentration, found that globulin can be pre- 

 cipitated from both normal and antipneumococcic serum by dilu- 

 tion with distilled water at hydrogen ion concentrations varying 

 from pH 5.0 to 7.0. The zone of maximal precipitation was ob- 

 served to lie between pH 5.5 and 6.0. By repeated precipitation at 

 pH 5.1 and pH 6.8, respectively, two fractions were obtained, one 

 of which was more soluble at neutral, the other at acid reaction. It 

 was shown that the two fractions combine with each other if the 

 solutions are mixed. The latter observation is of significance in 

 connection with the concentration of antipneumococcic serum bi- 

 valent for Types I and II. 



After experimenting with water precipitation, Goodner 528 rec- 

 ommended the employment of preliminary water tests for each lot 

 of serum to determine its suitability for concentration. By observ- 

 ing the dilution of serum with distilled water necessary to cause 



