248 BACTERIOLOGY 



Micrococcus tetragenus mobilis ventriculi. — Mendoza 

 found in the contents of the stomach motile cocci which 

 tend to arrange themselves in fours, and appear as tablet- 

 cocci. Bound colonies form on the gelatine plate, which 

 appear finely granular under a low power and are sharply 

 defined, while on thrust-cultures a dirty-white layer is 

 visible. When the cultures stand for some time they take 

 on a yellowish-brown colour, the sugar titit. The gelatine 

 is not liquefied. 



Bacterium lactis aerogenes. — In the normal small in- 

 testine of young animals and sucklings Escherich found a 

 micro-organism which Abelous detected almost as a rule 

 in the stomachs of adults also. They are short rods with 

 rounded ends and destitute of motility. On the gelatine 

 plate roundish colonies form, which appear yellow in the 

 deeper parts. In thrust-cultures growth takes place along 

 the canal and on the surface a prominence develops (nail- 

 culture). The gelatine is not liquefied. A shining layer 

 develops upon agar, having the centre whiter and denser than 

 the periphery. This layer spreads out very rapidly over 

 the surface, and soon appears permeated by bubbles of 

 gas. On serum there forms a greyish moist deposit with 

 irregular edges, which rapidly extends without liquefj'ing 

 the medium, On potato there develops a white coating per- 

 vaded by gas-bubbles, which becomes yellowish and fluid. 

 Gas-bubbles appear on other media also, but on gelatine 

 and agar only when glycerine is added. It grows on milk 

 even when oxygen is excluded. Curdling of milk is caused 

 by the growth of the bacterium, and the lactose is very 

 rapidly and energetically converted into grape-sugar. It 

 has no action on albuminoid bodies. 



Bacillus indicus. — Koch found in the gastric contents of 

 an Indian ape a fine, very short bacillus with rounded ends, 

 and characterised by a tolerably distinct motility. The 



