MORPHOLOGY OF CAUSATIVE AGENTS. 117 



Both staphylococcus cereus albus and staphylococcus cerem 

 flavus, which are uncommon, are characterized by not 

 liquefying gelatin. The one possesses a wax-like white 

 color, while the other generates a wax-like yellow pigment. 



Fig. 38. Staphylococcus pyogenes albus (Jakob). 



Streptococcus Pyogenes (Erysipelatis). This appears 

 in the form of nonmotile micrococci arranged in chains 

 of greater or lesser length. (Fig. 39.) They vary in size 



- 39- Streptococcus pyogenes (Jakob). 



between 0.3 p- and i A*. They stain readily, and by Gram's 

 method. The temperature-optimum is between 30 C. 

 (86 F.) and 37 C. (98.6 F.) ; they develop also at 



