Generic Characters in the Coccaceae 



TABLE 8. 

 Correlation between Habitat and Chromocenisir. 



177 



Table 8 brings out some of the most definite relations yet con- 

 sidered, between habitat and chromogenesis. It is evident that the 

 white and orange forms are largely parasitic, and the yellow and red 

 forms as distinctively saprophytic. More than half of the white 

 and more than two-thirds of the orange chromogens come from the 

 first two habitats, while only one-third of the yellow forms have such 

 an origin. The distribution of the red pigment-formers is even more 

 notably saprophytic. Only one culture out of 25 occurred among 

 the 229 cultures from the body. 



TABLE 9. 

 Correlation between Habitat and Gelatin Liquefaction. 



The table for habitat and gelatin liquefaction (Table 9) shows 

 this property occurring among the earth and water forms to a less 

 degree than among the parasitic cocci. This fact, and the fact 

 that the parasitic forms are high acid-producers, as noted above, 

 are of practical significance in connection with the bacteriological 

 analysis of water. It has long been suspected that acid producti(m 

 and gelatin liquefaction were associated with intestinal organisms, 

 and we have here a measure of the truth of this proposition, in the 

 case of the cocci at least. From the food conditions which obtain 

 in the ahmentary tract, and to a less extent on the outer surfaces 

 of the body, it is natural that these properties should be highly 

 developed. 



The forms from Habitat II (the surfaces of the normal body) 

 group themselves most abundantly at two extremes, 68 being non- 



