BACILLUS ALVEI. 



345 



The bacilli grew well at 20 C., on various nutrient Cultivations. 

 media; in gelatine plates they form at first small round 

 or oval discs, in which, with a low power, peculiar 

 markings, occasioned by the bundles of bacilli, is notic- 

 able. The colonies become gradually pear-shaped, and 

 from the pointed end of the pear prolongations begin to 

 shoot out into the gelatine. These prolongations can 

 be still better studied in stroke cultivations on gelatine 

 plates. In that case growth in the first place occurs 



Fig. 94. Cultivation of bacillus alvci. 



(t, growth on gelatine plates X 80. 



b, puncture cultivation in nutrient jelly X 4. 



along the track of the needle ; but soon small lateral 

 projections appear, and from these bands of bacilli grow 

 out often in a single row, often two or three bacilli side 

 by side; these projections gradually curve, and form 

 well-marked circles; from these circles new projections 

 proceed ; the individual branches also anastomose with 

 each other. In the immediate neighbourhood of the 

 bacilli the gelatine becomes at the same time fluid, so 

 that ultimately there is a network of fine canals in the 



