336 APPLICATION OF METHODS OF BACTERIOLOGY 



of protective powers. No antitoxic power could be demon- 

 strated in the serum of the treated animals. The extremely 

 limited degree of the protective power of antistaphylo- 

 coccus serums makes them useless for curative purposes in 

 human beings, as Petersen calculated that an adult would 

 require from 350 to 700 c.c. of the serum at a single dose, 

 as judged by its effects on the lower animals. 



OTHER COMMON PYOGENIC ORGANISMS. 



MICROCOCCUS PYOGENES (Rosenbach), Migula, 1900. Synonyms: 

 Staphylococcus pyogenes albus, Rosenbach, 1884; Micrococcus pyo- 

 genes albus, Lehmann and Neumann, 1896. 



MICROCOCCUS CITREUS (Passet), Migula, 1900. Synonym: Staphy- 

 lococcus pyogenes citreus, Passet, 1895. 



The pus of an acute abscess in the human being may 

 sometimes contain organisms other than micrococcus aureus. 

 Micrococcus pyogenes and micrococcus citreus may be found. 

 The colonies of the former are white, those of the latter 

 are lemon yellow. With these exceptions they are in all 

 essential cultural peculiarities similar to micrococcus aureus. 

 As a rule, they are not virulent for animals, and when they 

 do possess pathogenic properties, it is in a much lower 

 degree than is commonly the case with the golden micro- 

 coccus. Streptococcus pyogenes is also present sometimes. 

 The commonest of the pyogenic organisms, however, is 

 that just described, viz. : micrococcus aureus. 



An organism that is almost universally present in the 

 skin, and is often concerned in producing mild forms of 

 inflammation, is Staphylococcus epidermidis albus (Welch), 

 an organism that readily may be confused with micrococcus 

 pyogenes. It differs from the latter by the slowness with 

 which it liquefies gelatin and by the comparative absence 



