1900] 
| 900 CHROMOGENIC BACTERIA 38 
I 
_ medium sterili . 
ee an eat days in succession in streaming steam, 
ipon such a piece of ure of B. polychromogenes is inoculated 
"produced, which SE sae a deep blue very soluble pigment 
the medium, colori iffuses slowly through the whole mass of 
into fifteen da iyi the latter an intense indigo blue, In from 
lass, and has aerate matter has penetrated the entire 
ee ot Dito 2 it uniformly and so intensely that the 
potato, the more oa almost black. The more porous the 
the pigment is panei 3 and uniformly is it colored, since 
the color remains a ieee Sbsenee of air. For some time 
it purple, and th the — intensity, then it becomes violet 
longer able to aie OWlns either to the organism being no 
the various as « pigment to replace that being reduced by 
the production 2 substances present in the potato, or owing 
color begins to ee reducing agents by the culture itself, the 
Ridly, the color Decolorization proceeds more and more 
s being “s aa the surface of the medium exposed to the 
‘Boumes a dirty oe disappear. The culture medium finally 
Mo thin slices and eee Generally, cutting up the potato 
tction of a bl SEponne them to the air leads to the pro- 
‘00 old, ue again by oxidation, providing the culture is not 
quite soluble in 
The bi 
hi, ue pigment is very soluble in water, 
her, chloroform, - 
Mlle alc 
Yenzine, = a in strong alcohol, in et 
‘Ttnately extractio ef therefore, ‘5 the best solvent; but unfor- 
reducing Dcian n with water removes such an amount of. 
“ohol, the str ces that it was found necessary to employ dilute 
Mesent in th ength of the latter varying with the moisture 
| e culture to be extracted. 
In or 
s cut i socpassesages the pigment, the piece of culture medium 
der that n slices and exposed to the air for a short time in 
formed, “a much of the blue pigment as Po 
: OWed to . alcohol is then poured ovet 
7 Fed off, and or some hours, the blue alco 
alli aarenetebater of the solvent is 
ong as any coloring matter can be re 
holic solution 1s 
made. This 
moved. The 
