THE GENUS AUROCOCCUS 173 



The higher animals appear to be parasitized by staphy- 

 lococci closely related to those found in man. The cocci 

 present as secondary invaders in the tuberculous nodules 

 of cattle have been studied by several observers; and the 

 results of earlier workers, with a study of thirty-two 

 new cases, are cited in an admirable paper by Oestern 

 (1904). The author x concludes that the organisms 

 are identical with those found in human suppurations. 

 The commonest form in twenty-six cases was a white 

 coccus, positive to the Gram stain, liquefying gelatin and 

 coagulating milk, which we define later as our Albococcus 

 pyogenes. An orange form was found seven times and 

 a yellow micrococcus three times. 



It has been held by almost all medical observers that 

 the distinction between the three chromogenic varieties 

 of "the staphylococcus " is an insignificant one. Thus 

 Neisser and Lipstein (1903) hold that the white pyogenic 

 cocci are indistinguishable from the orange forms in dis- 

 tribution or pathogenicity or in any biological properties, 

 save pigment formation. They believe the white cocci 

 arise from orange strains which have lost their chromo- 

 genic power through the effect of external conditions. 

 In a recent review, Courmont (1906) will scarcely allow 

 varietal rank to the white and yellow forms. 



The most important evidence of the unity of the staphy- 

 lococci lies in experiments which have demonstrated the 

 variability of their chromogenic power. Rodet and Cour- 

 mont (1890) claim to have witnessed, in successive cultures, 



