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Society Proceedings (122). 



and horse sera were determined by fraction ing the diluted serum 

 with ammonium sulfate. The analyses in parts per hundred 

 were as follows: 



Albumen. Globulin. 



Horse 2.6 3.5 



Rabbit 3.41 2.27 



Sterile albumen and globulin were obtained respectively from 

 horse and rabbit sera under sterile conditions. The albumen was 

 precipitated with ammonium sulfate. The globulin was prepared 

 by saturating diluted rabbit serum with C0 2 and so did not 

 represent the true globulin fraction of the serum. 



The horse serum was diluted until it contained 2.27 grams of 

 globulin per hundred c.c. and sufficient horse-serum albumen 

 added to bring the percentage of albumen to 3.41 grams per cent. 

 Rabbit serum was diluted and rabbit-serum globulin added so 

 that the percentages of albumen and globulin were the same as 

 those of horse serum. Flasks of 20 per cent, media were prepared 

 with the modified sera. When growth and streptolysin estima- 

 tion were made with growing cultures in these media it was found 

 that the reversed ratio of albumen to globulin had no effect on 

 the type of curve obtained. The curves in the modified sera 

 were similar to those in normal serum media. Hence it appears 

 that albumen and globulin do not enter into any of the peculi- 

 arities of growth exhibited by hemolytic streptococcus. This 

 fact was further substantiated by a study of the proteolytic 

 enzyme of these bacteria, because the enzyme acted similar to 

 erepsin and did not digest serum albumen and globulin. Further- 

 more the addition of large amounts of albumen and globulin did 

 not modify the curves. 



Growth and hemolysin were next studied in peptone. Two 

 preparations of peptone were used. These were similar except 

 one was partially hydrolyzed and the other broken until further 

 digestion with active trypsin gave no increase in amino nitrogen. 

 The peptone was boiled, filtered through a 10-pound filter and 

 added to beef infusion. Analyses of the media prepared with 

 these peptones after autoclaving were as follows: 



Total N. Amino N. 



Grame per 100. Per Cent, of Total N. 



1 0.27 14.9 



2 0.28 41-8 



