178 C.-E. A. WINSLOW AND ANNE F. ROGERS 



liquefiers and 66 active liquefiers, while only 36 occupy the inter- 

 mediate position, which is of most frequent occurrence in all the other 

 habitats. It is probable that this may be accounted for by the pres- 

 ence, in Habitat II, of two distinct series the white and colorless 

 forms, which, as we shall see later, are non-liquefiers, and the orange 

 forms, which peptonize strongly. 



From a general survey of our habitat studies it is evident that 

 the forms from the body exhibit quite different characteristics from 

 those of the water and earth cocci. The parasitic forms generally 

 react positively to the Gram stain, give only fair surface growths 

 on the surface of artificial media, produce acid in dextrose and lac- 

 tose, grow best at 37, produce no pigment or a white or an orange 

 pigment, and liquefy gelatin. The saprophytes, on the other hand, 

 are more apt to occur in packets, to be Gram-negative, to grow 

 abundantly on artificial media, best at 20, to produce yellow and 

 red pigments, and to exert little action on sugars and gelatin. The 

 air cocci are generally intermediate in character between the two 

 groups, but show special powers of nitrate reduction. 



2. GROUPING OF CELLS, AND DIMENSIONS. 



The cocci, as noted above, were divided into two classes only, 

 according to the character of the cell aggregates; 155 cultures showed 

 the packets or sarcina-grouping, and 345 did not. 



TABLE 10. 

 CORRELATION BETWEEN CELL-GROUPING AND GRAM STAIN. 



We have pointed out above that packets are most abundant among 

 the saprophytic cocci of the earth and water. Table 10 shows 

 the relation between cell-grouping and the Gram stain, clearly 

 indicating that the packets tend to be Gram-negative, while a ma- 

 jority of the other forms give a positive reaction. 



Table n shows a distinct correlation between cell-grouping and 

 the vigor of surface growth. A large majority of the non-packet- 



