34 RELATIONSHIPS OF THE COCCACEyE 



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, n species; red liquefiers, 12 species; 

 blue and violet forms, 3 species. Similarly his genus 

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

 fiers, 1 6 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 



