QUALITATIVE BACTERIOLOGICAL ANALYSIS. 58 



irregular forms are seen in which the bacilli appear packed in 

 parallel rows. 



Gelatine- stab. The gelatine is liquefied in the form of a 

 funnel ; a flocculent deposit appears at the bottom and a tough 

 pellicle on the surface. 



Agar-slope. A thick white growth appears, which later 

 becomes wrinkled. 



Glucose-gelatine. No gas formation. 



Nitrate-broth. No reduction of nitrates. 



Broth. A pellicle forms on the surface, which later becomes 

 wrinkled and furrowed. 



Potato. A thick white growth, which is often thrown into 

 large transverse folds ; later, dry white granules may appear 

 on the surface. 



Peptone-water. No indol reaction is obtained. 



Litmus-whey. After seven days incubation the blue colour 

 disappears and the medium is rendered faintly alkaline. 



Milk. At 37 C. milk is peptonised and partially digested. 



Microscopical Appearance. A large bacillus with rounded 

 ends, often in pairs and chains. It has a slow waggling movement, 

 and forms oval spores. It is strongly aerobic, and stains with 

 Gram. Sewage varieties of B. subtilis and B. mesentericus have 

 been described by Houston. 



B. Mycoides. 



This bacillus is said to be identical with the B. ramosus in all 

 its cultures. It is found in sewage and also in surface waters. 



Colonies on Gelatine Plates. The colonies appear as white 

 patches, from which numerous irregular processes extend on all 

 sides into the gelatine, producing an almost mould-like growth. 

 The gelatine becomes liquefied after about seventy-two hours 

 incubation. 



Gelatine-stab. A white growth occurs along the stab, from 

 which processes extend horizontally into the gelatine, producing 

 a tree-like growth ; later, liq uefaction occurs. 



Agar. A white, rather dry growth, from which mould-like 

 processes extend at the margin. 



Glucose-gelatine (shake). No gas formation. 



Peptone-water. No indol reaction. 



