002 ^OX-PATHOGENIC BACILLI. 



time liquefied ; a similar appearance is observed when gelatin plates are pre- 

 pared arid kept in an atmosphere of hydrogen. When successive cultures 

 are made in gelatin tubes the bacillus gradually loses its vigor of growth 

 and the colonies have a different appearance ; the thread-like outgrowths are 

 no longer seen, or are developed to a slighter extent, and the spherical or 

 balloon-shaped colonies are filled with a clouded liquid, while a thick sedi- 

 ment is formed. In gelatin stick cultures development occurs along the 

 line of puncture to within one or two centimetres of the surface; at the end 

 of two days numerous branching filaments are given off, which give the 

 growth the appearance of a hairy caterpillar. In nutrient agar stick cul- 



FIG. 285. FIG. 236. FIG. 287. FIG. 238. FIG. 239. 



FIG. 235. Bacillus liquefaciens magnus; stick culture in nutrient gelatin. (Luderitz.) 

 FIG. 236. Bacillus radiatus ; stick culture in nutrient gelatin. (Luderitz.) 

 FIG. 237. Bacillus spinosus ; stick culture in nutrient gelatin. (Luderitz ) 

 FIG. 238. Bacillus liquefaciens parvus; stick culture in jiutrient gelatin. (Luderitz.) 

 FIG . 239. Clostridium f oetidum ; culture in nutrient agar, under oil. (Liborius.) 



tures growth occurs to within one centimetre of the surface; it is branching 

 in character and resembles that of Bacillus liquefaciens magnus, but the 

 filaments are more delicate; later the principal branches are thicker, and 

 they are surrounded by a denser mass of fine filaments, among which some 

 thick outgrowths are also seen. Blood serum is rapidly liquefied by this 



