[Vou. 1 
60 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
Air cocci 
н> 
21’ f Massicot yellow 
217 e Intermediate between massicot and straw 
yellow 
217 d Straw yellow 
21’ b Amber yellow 
19' d Naples yellow 
19’ b Mustard yellow 
19' Primuline yellow 
19 f Maize yellow 
19 d Buff yellow 
3’ b Light Jasper red 
One form did not grow. 
16 
кі m mL. ва іа ро 
Skin соссі 
19 f Maize yellow 1 
19 d Buff yellow 1 
19 b Apricot yellow 2) 5 
217 e Intermediate between massicot and straw 
yellow 1 
White 1 
At first glance the color of the pigments produced by the 
organisms would seem to furnish one mode of differentiation. 
In the majority of cases the salivary cocci produced cinnamon 
colored pigments, whereas pigments of a yellow color were 
usually produced by the air and skin forms. Closer inspection 
shows, however, that some of the salivary cocci, as well as 
the air forms, produce a maize yellow and a mustard yellow 
pigment; also that a maize yellow pigment and one inter- 
mediate between massicot and straw yellow are produced 
by representatives of both the salivary and skin cocci. It 
is apparent that these intergradations make the factor of pig- 
ment production largely inapplicable as a differential test. 
In milk the salivary соссі with one exception produced acid 
and coagulated the medium, whereas none of the air forms 
and but one of the skin соссі gave this combined reaction. 
This attaches to milk considerable value as a differential me- 
dium. In the media containing the various organic substances 
