34 RELATIONSHIPS OF THE COCCACE/E 



color of the colonies. The unnatural collocation of 

 organisms produced at the end of such an arbitrary 

 scheme may be imagined. Under the white non- 

 liquefying group, for example, the streptococci were 

 distinguished by their small isolated colonies from 

 another group which included diplococci, micrococci, 

 and sarcinae. Dyar (1895), too, made his primary 

 division of the micrococci into liquefying and non- 

 liquefying forms. Each of ' these groups was then 

 separated according to acid production, and still finer 

 divisions were based on chromogenesis and other charac- 

 ters. 



Migula (1900), on the other hand, makes his primary 

 division of the cocci, which have been cultivated on 

 gelatin, according to chromogenesis. Under Micrococcus 

 there are seven primary divisions; white non-liquefiers, 

 60 species; white liquefiers, 41 species; yellow non- 

 liquefiers, 20 species; yellow liquefiers, 35 species; 

 red non-liquefiers, 11 species; red liquefiers, 12 species; 

 blue and violet forms, 3 species. Similarly his genus 

 Sarcina includes 6 white liquefiers, 9 white non-lique- 

 fiers, 16 yellow liquefiers, 14 yellow non-liquefiers, 2 

 brown forms, and 5 red forms. 



Chester's classification (Chester, 1901), is based on 

 the same general principles as that of Migula; but within 

 the various color classes are sub-groups marked by the 

 vigor of growth at various temperatures, and by the 

 appearance of surface growths on various media. This 



