PRODUCTION OF ANTIPNEUMOCOCCIC SERUM 563 



duction, Felton (1928) found that removal of the acid fraction 

 from the crude, water-insoluble precipitate carried most of the 

 phosphorus and lipids, but the author hesitated to conclude that 

 these substances were entirely responsible for chill-production, al- 

 though concentrates so prepared were reported to be essentially 

 free from the substance provoking reactions. In 1930, Felton 404 

 stated that, notwithstanding the fact that elimination of the acid 

 fraction was the most important single step in preparing chill-free 

 concentrates, toxins due to bacterial contamination during manu- 

 facture and storage might also be a contributory factor. In com- 

 paring chill-producing concentrates with bland preparations, Fel- 

 ton and Kauifmann (1931 ) 427 found the former to contain some 

 residual acid fraction, a higher phosphorus and lipid content, and 

 more ammonia and non-protein nitrogen. Of these factors, the acid 

 fraction was considered to be the most important. However, it is 

 not always possible to obtain an acid fraction precipitate from 

 chill-producing lots as reported by Barnes and Kramer (1933). 83 

 Complete reconcentration of the serum may render some, but not 

 all, of the preparations suitable for use (Park, 1930 1053 ). 



Banzhaf and Klein (1930) 72 described the details of a method of 

 preparing chill-free concentrates. After dialysis, sodium sulfate or 

 sodium chloride is added and, after storage in the cold overnight, 

 the reaction is adjusted to pH 5.1 to 5.3. Insoluble substances, 

 fibrin, fibrinogen, euglobulin, and chill-producing substances floc- 

 culate and are removed. The material is filtered and the reaction of 

 the fluid is adjusted to pH 6.8 for further precipitation, princi- 

 pally of fibrin. The sediment is removed by filtration and the 

 water-insoluble precipitate prepared by the usual technique. In the 

 alcohol method of concentration, Felton (1931 ) 408 advised the re- 

 moval of the acid fraction at pH 5.0. Concentrates prepared by 

 this means, particularly when precautions are taken to avoid de- 

 naturation by the alcohol, have been for the most part satisfac- 

 tory, although lots that occasion reactions are sometimes encoun- 

 tered. 



