234 



II. BACILLI. 



(For the characters of the genus, see p. 172.) 

 A. BACILLI PATHOGENIC ix MAX. 



Bacillus anthracis. 

 (Bacteridie du charbon, Milzbrandbacillus.) 



Morphological Kods 5 to 20 p. in length, and 1 to 1*25 p.. in breadth, 

 anthrax which divide when they have grown to about double their 



length. Bacilli are frequently found with a commencing 

 transverse division in the middle; many are bent at 

 this place, or are loosely connected, the two segments 

 forming an angle with each other. The rods present 

 somewhat different appearances in preparations which 

 have been made by drying a thin layer of blood, 

 of the pulp of the spleen, &c., and subsequent 

 staining. The chains of bacilli are then dis- 

 tinctly segmented ; the individual bacilli do 

 not show any difference in length and breadth, 

 "ri 62 kut are truncated a t the ends, not rounded 

 off; the segments are not divided by a trans- 

 verse line, but the clear line of division has a small 

 swelling in its middle, and the point of union between 

 the two segments presents a slightly knob-like thicken- 

 ing. Flagella have not been observed ; the rods are 

 always motionless. On cultivation on different media 

 the thickness of the rods may vary somewhat, without 

 the characteristic form being otherwise altered. Mani- 

 fold involution forms occur under unfavourable circum- 

 stances. (See page 157.) 



On suitable soil, and at a temperature of about 36 

 C., the bacilli form long threads, which may be much 

 twisted, and often attain 100 times the length of 

 the original bacilli. After some time small, highly 

 refracting granules appear at regular intervals in the rod, 

 and develop into roundish spores, while the threads 



