302 BACTERIOLOGY. 



needle track. Processes shoot out from these 

 masses, and extend through the gelatine for long- 

 distances. They are thickened at points in their 

 course, and clubbed at the ends. The gelatine is 

 gradually liquefied, and the bacilli form a loose, 

 white, flocculent deposit at the bottom of the tube. 

 The liquid in the tube becomes yellowish in colour 

 after a time, and gives off an odour of stale but 

 not ammoniacal urine. The colour and odour are 

 distinctive also of the disease attributed to the 

 bacilli. In plate-cultivations, the bacilli grow out 

 in series of rods in single file, or in rows of several 

 side by side. The processes which are formed, 

 tend to curve, and at a short distance from the 

 track of the needle-streak form a distinct circle, 

 from which another process grows out, and a fresh 

 circle is developed. The gelatine in the vicinity 

 of the bacilli gradually liquefies, and channels are 

 formed in the gelatine in which the bacilli move 

 backwards and forwards. On nutrient agar-agar 

 a whitish layer develops, consisting of bacilli 

 arranged side by side, which in a few days are 

 replaced by rows of spores similarly arranged. On 

 potatoes they form a dryish yellow layer, and in 

 milk a tremulous jelly. A cultivation of the bacillus 

 in milk, sprayed over a honeycomb containing a 

 healthy brood of bee larvse, produced the disease 

 known as " foul -brood." Adult bees fed on ma- 

 terial containing bacilli became affected ; inocula- 

 tion of mice and rabbits with the bacillus gave 



