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 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 fgrm was found seven times and 



a yellow micrococcus three times. 



ft* 



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 pathogenicfty 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, Coyfrmont (1906) wall scarcely allow 

 varietal rank to the ^ifte and yellow forftik 



The most importarft 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, 



