224 



HAROLD C. ROBINSON AND LEO F. RETTGER 



made faintly alkaline to litmus. The results are given in the 

 following table: 



Gonococcus (287) 



Pneumococcus (M) 



Pneumococcus (697) 



Meningococcus (M) 



Meningococcus (200) 



B. pertussis 



B. diphtheriae (Y. M. S.) 



M. melitensis 



Streptococcus (urine) 



FOBTY-EIGHT HOURS 



"Casein C" 

 8 per cent 



+ + 



+ =*= 

 + + 

 + + + 

 + + 

 + 



Lactalbumin 

 products 

 2 per cent 



+ + 



Medium III 



+ + + 

 + + + 

 + + + 



As was to be expected, medium II gave the poorest results. 

 The gonococcus, pneumococcus, meningococcus and B. per- 

 tussis grew on at least one of these media (I), with the exception 

 of pneumococcus 697. The same results were obtained with 

 transplants made from these cultures to the same media. 



Since tryptophane was found to be absent from all of the acid- 

 digestion products of the proteins used, some experiments were 

 conducted in which tryptophane was added to the different 

 digestion products. The tryptophane exerted very little, if in- 

 deed any, influence on the nature and luxuriance of the different 

 growths. * 



Comparison of growths on Witters peptone, opsine, lactalbumin 

 product paste, Casein C, and Casein C, edestin and lactal- 

 bumin product paste (combined) 



Medium I. Witte's peptone 1 per cent, NaCl 0.5 per cent. 

 Medium II. Opsine 2 per cent. 

 Medium III. Lactalbumin product paste 2 per cent. 

 Medium IV. Casein C product 8 per cent. 

 Medium V. Casein product C 2.5 per cent + edestin prod- 

 uct 2.5 per cent + lactalbumin product 2.5 per cent. 



