NON-SPECIFIC PYOGENIC COCCI 197 



from mastitis in cows, which differed from typical Micrococcus 

 albus principally in its lack of power to liquefy gelatin. It prob- 

 ably represents a variety merely. 



Micrococcus ovis. An organism resembling Micrococcus albus 

 was described by Nocard as the cause of gangrenous mastitis in 

 sheep. With the exception of its specialized pathogenesis, it 

 differs but little from typical Micrococcus albus. 



Micrococcus epidermidis albus. This is probably a variety 

 of the Micrococcus albus found in the deeper layers of the skin, and 

 the common cause of " stitch abscesses." 



Micrococcus cereus (albus and flavus). These organisms 

 differ from the micrococci heretofore described in producing a 

 waxy growth upon artificial media, hence the name cereus (wax). 



Streptococcus pyogenes 



Synonyms. Streptococcus erysipelatos ; Str. puerperalis; Str. 

 articulorum; Str. pyogenes malignis; Str. septicus; Str. scarlatinosus. 



Pasteur first recognized the Streptococcus in pus, but Ogsten, 

 between 1880 and 1884, first definitely isolated and described it. 

 Fehleisen, in 1883, found the organism in erysipelas, and Rosen- 

 bach described it in detail and gave it its present name. 



The student will find no more puzzling group of organisms than 

 the Streptococci. They have been found in connection with all 

 types of inflammatory processes. Some strains are exceedingly 

 virulent, others wholly lack the power of disease production. 

 Differences have been recorded in the cultural characters of isola- 

 tions from different sources, and the species split into several on 

 the basis of these variations. None of these classifications has 

 proved to be wholly satisfactory, and, for the present, it is probably 

 best to treat all the forms as varieties merely of one rather poly- 

 morphic species. 



Distribution. Streptococcus pyogenes does not adapt itself 

 as readily to a saprophytic mode of existence as do the staphylo- 

 cocci. It is commonly present upon the skin of man and animals, 

 and has been isolated from a great number of different inflamma- 

 tory and suppurative processes in both. 



Morphology and Staining Characters. This organism is a 



