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Beijerinck at Delft, there regularly occurred in these cultures a 
microbe which drew the attention by the formation of a red and 
yellow colouring-matter on meat-agar and meat-gelatine. The colonies 
are of a bright yellow colour, whilst a red colouring-matter diffuses 
in the culture-plate. 
This bacterium shows itself more especially in cultures with citrate 
and tartrate in large numbers, so that in using these salts the above 
mentioned species can be obtained in great numbers. 
If in the same culture-liquid inocculation is repeated twice or three 
times at a temperature of 23° and a titre of + 35 ec. N. per 
100 ec.e. culture-liquid, this bacterium is often accumulated almost to 
pure culture. 
Description of Bacillus erythrogenes. 
Bacillus erythrogenes are among the very strong oxidating fer- 
ments; both sugars and salts of organic acids and also albumen are 
assimilated. In tap water 0.05°/, K, HPO, a fair growth takes 
place in the presence of ureum, if one of the following compounds 
as a carbon-source is added: glucose, maltose, cane-sugar, asparagine, 
caletum- and natriumsalts of the volatile fatty acids (except of formic 
acid, which gives a slight growth) and the multibasie acids, such as 
apple acid, lactic acid, lemon acid, argol acid and amber acid (except 
oxalic acid). 
Milk appeared to be a very suitable culture-medium. The develop- 
ment herein is attended by the appearance of a disagreeable sweet 
smell. 
Even calciumhumate added as a carbon-source causes growth and 
therefore ureum-splitting. 
Amylum, however, is not affected, so that evidently no diastatic 
enzym is formed. 
The yellow colouring-matter belongs to the body of the bacteria 
and arises independent of the composition of the medium; however 
for its formation the influence of light is necessary. 
The red, diffusing colouring-matter arises only in case the feeding 
takes place with albumen and the light is excluded. Arisen in the 
dark, this colouring matter will soon be decomposed when exposed 
to the light. 
Cultivated on meat-agar while light is excluded, the white colony 
shows itself on a fine red diffusion-field ; cultivated in the presence 
of light, there arises a bright yellow colony on a colourless field. 
What influence the two colouring matters have on the vitalfunctions 
of the microbe, could not be stated. 
