BIOCHEMISTRY OF STREPTOCOCCUS HEMOLYTICUS 



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The apparatus employed differed from that of Dyer (1916) 

 in that the heating of the flasks was done with gas instead of 

 electricity. By thoroughly insulating the flasks and connecting 

 tubes with asbestos it was possible to maintain a constant volume 

 throughout a long distillation. 



To test the accuracy of the method several preliminary deter- 

 minations of pure acids were first carried out. The results 

 obtained for formic, acetic, and caproic acids are to be found in 



table 1. Graphical representation of the distilling rates has 

 been made on logarithmic coordinate paper (see fig. 1). The 

 curves were found to fall between those of Dyer and those of 

 Wolf and TeKer. Attempts to use the color tests suggested by 

 Dyer did not meet with success and accordingly they were 

 abandoned. 



Lactic acid. It was presumed that the non-volatile portion 

 of the cultures consisted mainly of lactic acid; therefore the fol- 

 lowing quantitative method suggested by Fred, Peterson, and 

 Davenport (1919) was employed for its determinations: 



The residue from the distillation flask was carefully evaporated 

 on a hot plate to a volume of about 40 cc. This was placed in a 

 Soxhlet extractor and extracted with ether for fifty to sixty hours 



