[HARRISON A barlow] SLIME-PRODUCING ORGANISM 117 



With the exception of alcohol all of the carbohydrates mentioned in 

 the table favored pigment production. The period of pigmentation and 

 the amount of pigment produced varied with the kind and concentration 

 of the carbohydrates. Most of the cultures showed pigment in 24 to 

 48 hours, concentrations of 20^ and 30^ were but little slower than 1^ 

 and 10^. A few cultures required more than 2 days to show pigment, 

 thus mannite 20^^ took 3 days, 30^ took 6 days; maltose 10<^ took 4 

 days, 20^^ did not develop pigment and with SO^ there was no growth; 

 galactose 20^ and 30^ developed no pigment; starch 1^ took 3 days but 

 10<fc only 1 day; with glycerine pigmentation was delayed and weak, 

 strongest in 10^, though glycerine gave rich pigment in other media. 

 With no carbohydrates added to the agar, there was no pigment formed 

 or at most a faint green-blue discoloration. 



The pigmentation reached its maximum intensity in 4 or 5 days 

 from the time of inoculation and continued with little change for a 

 period of from 4 to 18 days, in moat cases about 12 days. The color 

 then changed gradually and diminished or disappeared, first in those 

 which were least pigmented and later from all. In strongly pigmented 

 media considerable pigment remained after 48 days or longer. These 

 remarks refer to the blue-green and red colors only, as these disappeared 

 ochre or rust color developed and remained. 



The Deep Blue Pigmentation. — In the deep blue pigmentation a 

 bright blue appeared usually within 1 or 2 days and diffused into the 

 agar beneath the most vigorous growth. It increased rapidly and 

 darkened to Prussian blue, reached its maximum, intensity at 20° C. 

 in 4 or 5 days and colored all of the medium. This color continued 4 to 

 18 days, usually 12 days, and gradually a wine color (Saccardo, vinosus) 

 appeared in the blue agar. This wine color was most evident by trans- 

 mitted light and was most intense beneath the band of growth. The 

 medium, up to this transparent, now became darker and opaque, and 

 green-blue with lead color gradually replaced the blue, while the wine 

 color remained. These colors then either gradually disappeared and 

 were replaced by ochre or they remained for 50 days or more. From 

 the surface of the water of condensation downward, the pigmentation 

 was in general like that in the agar of the slope, as above described, but 

 the changes were more rapid. The colors were replaced by amber which 

 darkened to ochre and rust color. The growth itself was less intensely 

 pigmented than the agar, into which the pigment readily diffused. 



The Faint Blue Pigmentation. — This was like the deep-blue but 

 was less intense. At first the color was blue-gray, then pale blue, blue- 

 green and lead color with a wine tint by transmitted light. These colors 

 faded out through violet and lilac and were replaced by amber or 



