PRODUCTION OF ANTIPNEUMOCOCCIC SERUM 559 



cent are in general use. At the Massachusetts laboratory, 0.2 per 

 cent phenol has been found to be satisfactory in maintaining the 

 sterility of therapeutic antipneumococcic serum. Care must be 

 taken that precipitation of protein does not follow the addition of 

 phenol and tricresol. 



Interest in the drying of serum as a means of preservation has 

 recently been revived, largely through the investigations of Mudd, 

 Reichel, Flosdorf and Eagle, 934 Elser, Thomas and Steffen, 354 and 

 Flosdorf and Mudd (1935). 454 The methods employed are applica- 

 tions of familiar physical conditions, namely, the use of low tem- 

 peratures and absence of moisture and oxygen. A detailed descrip- 

 tion of the equipment used for desiccating biological products, now 

 known as the "Lyophile apparatus" may be found in the publica- 

 tion of Flosdorf and Mudd. 454 



CHILL-PRODUCING FACTORS 



A disturbing, and as yet unsolved, problem is the occasional oc- 

 currence of a thermal reaction, or chills, in patients following the 

 administration of some lots of antipneumococcic serum. For a dis- 

 cussion of the clinical manifestations and management of the reac- 

 tion the reader is referred to Lobar Pneumonia and Serum Ther- 

 apy by Lord and Heffron 827 and the more comprehensive treatise 

 by Heffron. 601 The incidence of chills varies with different lots of 

 serum and with the method of refinement in the case of concen- 

 trated products. 



During the development of various methods of concentrating 

 antipneumococcic serum, attempts have been made to eliminate 

 non-essential constituents for the purpose of reducing reaction- 

 producing propensities. Unfortunately, some of the manipulations 

 involved are likely to result in varying degrees of denaturation of 

 the proteins associated with the protective antibody. Denaturation 

 may be considered as such an alteration in serum proteins that 

 they become insoluble in solutions of neutral salts. That these 

 changes may occur readily is shown by the work of Wu and Yen 



