PA Ee, ls lena oO ee eee 
~ Bists or 
1900] A NEW CHROMOGENIC MICROCOCCUS 271 
gelatine, on which the orange tint is slightly more marked, broth 
sediment, milk ring. Several trials to match this with the color 
wheel resulted in a range of: 
(z) (2) (3) 
Me - - - = + 765 Jae yee 
White - - - = 10 14 13 
Yellow - . > - oe 9 9 
Orange - - « “ 6 ; 6 
100 100 100 
Of these, (3) was almost the exact tint of my cultures, with the 
one difference of a slightly duller tone than that shown by the 
actual growth, particularly of a rather bright gelatine culture. 
But any one of these combinations gives a good idea as to the 
characteristic tint. 
By this method of description of colors there would be less 
possibility of confusion. The great advantage would lie in the 
‘ystematization of those chromogenic germs whose color is 
tirly constant on ordinary media for certain ages. For instance, 
the whole prodigiosus group produces a color in liquefied gela- 
= which may be variously described in the vocabulary of 
sche bacteriologists ; but the fact that it closely approxi- 
ay a color combination on the wheel of red 80 per cent., 
aaa per cent., is sufficiently definite. B. prodigiosus and B. 
tend alticus both give the above color to liquefied ‘gelatine in a 
ay culture. In addition to this B. ruber balticus produces a 
"Y Surface membrane of an entirely different shade, i. @., red 
ag cent., Orange 20 per cent. 
a. a difficulty pid this accurate determination of pigment 
duced Course, the liability of variation in the pigment pro- 
ee same germ on media made by different bacteriolo- 
It has on under different circumstances. aghie 
physical aig that if this organism is brought ees ‘ 
*cording ‘ soa ny a Series of broth and gelatine cu . ’ 
Media are not — suggestion,” such variations in stan 
“Jour. E We range. 
“xP. Med, 4 : 6009. 1889. 
