WHITE AND ORANGE STAPHYLOCOCCI 167 



of one characteristic of the St. aureus type tends in some degree 

 to be associated with the loss of others. Thus the white chromo- 

 gens are less actively pathogenic than the orange forms, less ac- 

 tively gelatinolytic, and slightly less vigorous in fermentative 

 action. The forms which fail to liquefy gelatin also tend to be 

 less active f ermenters than the liquefiers (table 5) . 



Finally in considering the significance of these relationships, it 

 must be pointed out that while the more typical and more vigor- 

 ous orange-pigment producing gelatin-liquefying, lactose-fer- 

 menting staphylococci are the characteristic forms found associ- 

 ated with pathological conditions the types of weaker biochemi- 

 cal powers are the ones most frequently isolated from air and dust 

 and other sources outside the human body. This correlation is 

 brought out in Table 5 and is made clear by an inspection of the 

 individual data presented in Table 10. It may plausibly be ex- 

 plained on the assumption that the loss of the bio-chemical pow- 

 ers characteristic of the typical St. aureus is promoted by the 

 unfavorable conditions of life outside the human body. 



REFERENCES 



Bronfenbrenner, J. 1918 A new indicator for direct reading of hydrogen ion 

 concentration in growing bacterial cultures. Journal of Medical 

 Research, 39, 25. 



Buchanan, R. E. 1915 Nomenclature of the Coccaceae. Journal of Infectious 

 Diseases, 17, 528. 



Chester, F. D. 1901 A Manual of Determinative Bacteriology. New York. 



Committee on Classification 1917 The families and genera of the bacteria. 

 Journal of Bacteriology, 2, 505. 



Conn, H. J., and Breed, R. S. 1910 The use of the nitrate-reduction test in 

 characterizing bacteria. Journal of Bacteriology, 4, 267. 



Dudgeon, L. S. 1908 The differentiation of the Staphylococci. Journal of 

 Pathology and Bacteriology, 12, 242. 



Gordon, M. H. 1906 Report on bacterial test whereby particles shed from the 

 skin may be detected in air. Supplement to the Thirty-fourth Annual 

 Report of the Local Government Board containing the Report of the 

 Medical Officer for 1904-1905, 387. 



Kligler, I. J. 1913 A systematic study of the Coccaceae in the collection of the 

 Museum of Natural History. Journal of Infectious Diseases, 12, 432. 



Migula, W. 1900 System der Bakterien. Bd. II. Jena. 



Rosenbach, 1884 Mikroorganismen be den Wundinfektionskrankheiten des 

 Menschen. Wiesbaden. 



Winslow, C.-E. A., and Winslow, Anne R. 1908 The Systematic Relation- 

 ships of the Coccaceae. New York. 



