270 BOTANICAL GAZETTE [ocroser 
It is evident that the color of the pigment produced by these 
germs, otherwise so similar, is of some importance in an effort 
to distinguish them. The descriptions are, for the most part, 
very meager in actual definite points, and it is doubtful if even 
the twenty-six standard tests given by Fuller™ as showing a high 
degree of constancy would serve to differentiate these forms, so 
general in character are the indicated reactions of the table. In 
regard to the chromogenesis, it would be of no advantage to 
multiply the list of adjectives, for few bacteriologists could 
describe in this way the exact tints of “pink,” “reddish” “rose,” oF 
“flesh color” with sufficient accuracy to make them unmistaka- 
ble. An article by E. B. Shuttleworth,*3 on “ Nomenclature of 
colors for bacteriologists’’ is one of the most recent attempts 
to systematize colors for bacteriology, This author’s classifica- 
tion gives under yellowish-pink three subdivisions: salmon, 
salmon-buff, and flesh color. I was unable, however, to obtain 
the plates or illustrations to which his numbers evidently 
referred, and without them the words do not give a very distinct 
visual image. . 
A simple and more exact method of determining the pig: 
ment color of germs is that of the use of a color wheel. Alittle 
contrivance of the kind often used in morphology and easily 
obtained is a wooden top with the various small color disks. A 
better determination, because of the more constant rate of revo- 
lution of the disks, can be made with a Bradley color whee 
standard Maxwell disks. By this means I obtained the following 
result in the case of the salmon-pink germ. 
An agar culture begins in a cream-pink grow ie 
determination is not necessary. After about 5-7 days it Ge 
to acquire the characteristic color, the composition of the ©? 
wheel for this age being near: red, 70 per cent.; white, - He 
cent.; yellow, Io per cent.. Later the color deepens with 
addition of a more orange tone, and remains almost cue: ) 
after two weeks for all culture media —agar (different reactions) 
“Jour. Expt. Med. 4: 609. 1899. 
“SJour, Amer. Pub. Herath. Assoc. 1895 : 406. 
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