physic:()-c:hemical properties 79 



enijilo) the e(|ui\alent of 50 c.c. of tlie "niother" culture per kilo 

 of body Aveight, in order to obtain approximately the same per- 

 centage of positi\e results. 



The reacting factors in the form of po\vder were stable. A 

 retest made six weeks after its preparation ga\'e identital results. 



In fmther experiments, all the steps in the j)rocedine of the 

 concentration of scarlet lexer toxin described by Shinn xvere car- 

 ried out as folloxvs: 



Fi\e hundred cubic centimeters of 1 per cent dextrose broth 

 of pH 7.6 was inoculated with Streptococcus heniolyticus scar- 

 la I i)uic, strain 4014. After txventy-four hours' incubation, the cul- 

 tiue xvas cooled in the refrigerator and diluted xvith 1,500 c.c. of 

 85 per cent alcohol containing 0.03 per cent glacial acetic acid. 

 The mixture xvas allowed to stand in the refrigerator for one 

 hour and then Avas filtered inider negative pressure through a 

 Buchner funnel, hard filter paper being used. The precipitate was 

 taken off the paper and dissolved in 0.85 per cent sodium chlo- 

 ride solution containing 0.5 per cent phenol and previously ad- 

 justed to pH 8. The suspension Avas then centrifugated at high 

 speed until it became perfectly clear. The sediment was discarded. 

 The supernatant fluid xvas re-precipitated with foin- vohmies of 

 acid alcohol and filtered as before; the supernatant fluid was dis- 

 carded and the precipitates xvere dried as in pre\ ioirs experiments. 

 The yield in dry powder was 1.76 gms. 



As may be seen, further purification of the material xvas ob- 

 tained through the remo\al of bacterial bodies and txvo-fold pre- 

 cipitation Avith acid alcohol. 



An amoimt of prjxvder equi\'alent to 50 c.c. of "mother" culture 

 gave positixe reactions in approximately 50 per cent of rabbits 

 tested. 



The xvork described demonstrated the possibility of some ]3ini- 

 fication and preserxation of active principles of the phenomenon 

 by means of precipitation xvith acid alcohol. Since accmate esti- 

 mation of the percentage of recovery is lacking, it is difficidt to 

 determine from these experiments xvhether the method offers any 

 opportunity for concentration of the principles (Shxvartzman, 



PURIFICATION OF B. COI.I PREPARATIONS 



Gentile (1934) reported shortly upon experiments xvith a 

 nucleoprotein fraction of B. coli. A 2 per cent solution of the 



