BACILLUS EAMOSUS 135 



is seen still more characteristically in the thrust-culture, pro- 

 cesses springing out radially from the needle-track, after the 

 manner of fibres from a tap-root. The aspect of the culture 

 has been aptly compared to that of an inverted pine-tree 

 (fig. 47). Older cultures are completely liquefied, and carry 

 a pellicle on the surface. The ramification is equally 

 distinct upon agar, and spores are also formed on potato. 

 On plovers' egg albumen there soon develop whitey-grey 

 colonies growing in root form, which become continually 

 more and more interlaced and entangled. The liquefaction 

 of the albumen is very tardy. 



Bacillus axirantiacus. — This bacillus, found by P. Frank- 

 land in deep wells, shows only a feeble motility. The rods 

 are often arranged in pairs, and grow out into threads. 

 Gelatine is not liquefied. Small raised colonies appear on 

 the plate, which are at first dark-coloured but subsequently 

 become bright orange-yellow, and this orange colour is also 

 very distinct on the surface of thrust-cultures, whereas the 

 track of the thrust shows no growth. On agar the deposit 

 is also of an orange colour. On potato the growth is re- 

 stricted to the spot inoculated. 



Eacillus aureus. — Adametz found the Bacillus aureus 

 in water, and Unna upon the skin of persons suffering from 

 sehorrhceic eczema. The rodlets are slender, have but slight 

 motility, and do not liquefy gelatine. The colonies on the 

 gelatine plate are irregular, coalesce with each other, and 

 develop a golden-yellow pigment, which also occurs in the 

 form of hemispheres on the surface of the streak-culture. 

 On potato the golden-yellow colour soon changes to a brownish 

 red. 



Bacillus bruneus, — The brown bacillus described by 

 Adametz and Wichmann shows small irregular rods. The 

 colonies, which do not liquefy the gelatine in their growth, 

 are rounded and whitish at first, later brown. The brown 



