102 RELATIONSHIPS OF THE COCCACE^ 



other observers. Gordon (1905) made a careful study of 

 the white staphylococci which will be discussed more fully 

 in Chapter IX. He examined 300 different strains in 

 eight differential media; and his results clearly indicate 

 the existence of a natural group of cocci which corre- 

 sponds to the one suggested by our small series of cul- 

 tures. All of his 300 white skin cocci were Gram-positive. 

 The commonest type coagulated milk, liquefied gelatin, 

 reduced nitrates, and showed high fermentative powers. 

 Gordon's work, however, threw no direct light on the 

 relation of these organisms to the orange forms. Dudgeon 

 (1908), in a more recent paper, reports a comparative 

 study of the orange and white staphylococci, inspired by 

 the work of Andrewes and Horder. He observed the lique- 

 fying power, the reducing power (as shown by lead acetate 

 and neutral red), and the acid production in eleven carbo- 

 hydrate media, of 46 strains of the orange type and 71 

 of the white. He concluded that all the staphylococci 

 studied were members of one species, altho only a 

 few of the strains were identical in all reactions. None 

 of his tests were quantitative, and no attempt was made 

 to analyze the figures with regard to the numerical dis- 

 tribution of various types. An examination of Dudgeon's 

 own tables shows that marked differences existed between 

 his two groups of organisms. All but two of his orange 

 strains liquefied gelatin, while only 60 per cent of his 

 white strains did so. Neutral red was reduced by 60 per 

 cent of the orange strains and by only 15 per cent of the 



