MICROCOCCUS PYOGENES. 181 



1885, ill, 165; Liibbert, " Biologische Untersuchungen iiber den Staph. 

 pyog. aureus," Wiirzburg, 1886. 



Introductory Remarks. For the comprehension of 

 the three forms given above as varieties of one form cer- 

 tain proof was hitherto lacking. R. 0. Neumann (A. H. 

 xxx, 1) furnished it when he observed that in orange- 

 colored colonies sometimes lighter white or yellow sectors 

 appear (similar to those in Micr. bicolor), and by inocula- 

 tion from these, cultures are obtained which still more mark- 

 edly present the formation of paler sectors. By repeated 

 consistent transfers in this way white and yellow cul- 

 tures can be grown from orange-colored cultures, and even 

 a red culture could be obtained. These new cultures re- 

 main in part permanent and in part revert to the original 

 form. Also consult Neumann concerning what was other- 

 wise known regarding the variations of this form. 



Highly probable synonyms : Micrococcus liquefa- 

 ciens conjunctive Gombert, Eisenberg, 301 ; Micro- 

 coccus flavus conjunctivas Gombert, Eisenberg, 302 ; 

 Staphylococcus salivarius pyogenes Biondi, Eisen- 

 berg, 309. 



The effort of various authors to found a specific differentiation of 

 the three forms upon varying virulence is wrong. In the first place, 

 the fact that the golden-yellow form is distinguished by special 

 virulence (v. Tavel, Lannelongue, and Achard) is disputed. Levy 

 found that the more common form in Strassburg was the white 

 form, and it was just as pathogenic. In the second place, it is easily 

 shown experimentally that enormous reduction of virulence is entirely 

 independent of the color (compare page 185). Growth without oxy- 

 gen which increases the virulence lessens the production of pigment. 



In the following the Micr. pyogenes aureus only is 

 particularly described. Regarding the /? citrous and Y 

 albus see page 187. 



Microscopic Appearance. Round, smaller or larger 

 cocci, on an average 0. 8 /*, in pairs or singly, usually in 

 grape-like clusters. Often they have a small division 

 cleft (8, x and xi). 



Relation to Oxygen. Grow well aerobically and not 

 so well anaerobically. 



Requirements as Regards Temperature and Nu- 

 trient Media. Optimum at 37, but grows well at room 

 temperature ; thrives upon all nutrient media, the pig- 



