WHITE AND ORANGE STAPHYLOCOCCI 161 



coccus aurantiacus, and Albococcus pyogenes. In view of the re- 

 sults here reported we are inclined to suspect that these earlier 

 results were perhaps due to the imperfections in technique which 

 Conn and Breed (1919) have shown to have been so common in 

 the past. In the small series of laboratory strains studied by 

 Kligler only 4 out of 11 orange strains failed to reduce nitrates 

 although 11 out of 12 results with white strains were negative. 



CONCLUSIONS IN REGARD TO THE JUSTIFICATION OF A GENERIC 



DISTINCTION BETWEEN THE ORANGE AND 



WHITE STAPHYLOCOCCI 



In view of the general results of this study of 180 strains of 

 staphylococci we are forced to conclude that the generic distinc- 

 tion between the white and orange staphylococci previously sug- 

 gested by the senior author is of doubtful validity. There is 

 indeed a slight difference in liquefying power between the two 

 chromogenic groups and of course, as is well known, a consid- 

 erable difference in pathogenic power. In view, however, of 

 the similarity between the orange and white pigment formers in 

 all the other characteristics studied it seems on the whole most 

 reasonable to consider them as belonging to a single generic group 

 which, according to the citations of Buchanan (1915) should 

 obviously bear the name Staphylococcus. This genus may be 

 defined as follows: 



Genus, Staphylococcus (Rosenbach) . Parasitic cocci. Cells in 

 groups and short chains. Gram positive. Produce on agar good 

 growth of orange color or abundant growth of porcelain white 

 color. Glucose, maltose and sucrose generally, and lactose fre- 

 quently, fermented without production of gas. 



CONCLUSIONS IN REGARD TO THE SPECIFIC TYPES TO BE INCLUDED 

 IN THE GENUS STAPHYLOCOCCUS 



Gordon (1906) classified his white staphylococci on the basis 

 of nine tests which included liquefaction of gelatin, coagulation 

 and peptonization of milk, reduction of nitrates and neutral red 

 and fermentation of lactose, maltose, glycerol and mannitol. 



