566 



WILLIAM S. STURGES AND LEO F. RETTGER 



These experiments were conducted over a considerable period 

 of time and often with different, media hence the strains em- 

 ployed constituted about the only constant factor. From a 

 comparison of curves 7 and 8, it appears that, within certain 

 limits at least, variations in initial concentration do not materi- 

 ally affect the course of the reaction. 





SORENSEN 



Chart 8. Meningococcus 



Chart 9. Meningococcus 



The pneumococcus 



Thirteen experiments were conducted with 4 different strains 

 of pneumococcus Here again autoh-tic changes were evident 

 to some extent in every instance but one (see chart 10). Num- 

 ber 6 was a control suspension which was heated at 70°C. to 

 destroj- the enzymes. For the sake of clearness the biuret curves 

 for 1 and 7 were omitted from the chart. Number 1 would 

 follow number 2 so closely as to coincide with it in the first part 

 of its course. Experiment 7 is the one in which no changes 

 were observed. If plotted, all of the points of this curve would 

 be found to he on the 0.2 ordinate. The material for this 

 particular experiment was obtained from a sugar medium and 

 the suspension was quite acid. It was found in certain experi- 

 ments not recorded here that when emulsions of the cocci pre- 

 pared from glucose agar cultures showed an acidity as high as 



