STUDIES ON CHROMOGENIC BACTERIA. I. 
NOTES ON THE PIGMENT OF BACILLUS POLYCHROMOGENES. 
E. M.CHAMOT and G. THIRY. 
(WITH SIXTEEN FIGURES) 
Tue Bacillus polychromogenes was first isolated from a well 
water of Nancy by Macé? in 1894, and since its first discovery 
he has met with this same organism on five different occasions in 
well and conduit waters of that city. Two years after its discovery 
it was again isolated from the same well, and was found to possess 
the same characters as in the previous case. The organism was 
then described by one of us under the name of Bacille poly- 
chrome.? 
These six colonies, found at different times, have varied neither’ 
in the original colonies nor on subsequent cultivation ; varieties 
are, therefore, still unknown. Neither has it been possible to 
obtain variation by culture methods, for although one of the 
original colonies has been grown in the laboratory since 1894, 
part of the time in America, no change has been observed. It has 
also been impossible to obtain a non-chromogenic variety = 
spite of all attempts. It seems more than probable that this 
beautiful species will be met with by other investigators, and 
therefore, although the present article has to deal with the 
pigment, a few words regarding the characteristic features of the 
bacillus may not be out of place. 
The B. polychromogenes was so named because of its 
power of giving a multiplicity of colors on ordinary culture 
media. On such media the organism produces at times blue, at 
peculiar 
de 
*Mack, E.: Traité pratique de Bactériologie. Ed. 3. 849-852. 1897: Atlas 
Bactériologie, f/ 29. ; 
iét 
*TuIRY, G.: Sur une bacterie produisant plusieures couleurs. C. R. de la Soc! 
de Biologie, 7 Nov. 1896. ee 
Contribution a l'étude du polychromisme bactérien. Archives d. physiol. ¥-9 
284-289. 1897. 
9. 1897 oe [DECEMBER 
