SPORE-FORMING PATHOGENIC ORGANISMS 75 



gangrene. Wyatt Wingrave (Medical Press, 1014, 32) 

 says simple acid-fast bacilli are found in chronic ear 

 discharges, atrophic rhinitis, faeces, lingual accumulations, 

 and in fact in any situation where bacilli grow in the 

 presence of fat." Sanguinetti has found them in distilled 

 water. 



CHAPTER VI 

 SPORE FORMING PATHOGENIC ORGANISMS 



OF the many organisms recognised as distinctly patho- 

 genic, only six are known to produce spores viz., B. an- 

 thracis, B. tetani, B. botulinus, the bacillus of malignant 

 oodema, and two organisms pathogenic for animals alone 

 B. Welchii and B. (Clostridium) Chauvcei. With the 

 exception of B. anlhracis, they are anaerobes. 



The Anthrax Bacillus. 



Morphology. B. antliracis varies in length from 5 to 

 6//, in breadth from 1 to 1'5 /n. It is aerobic, and faculta- 

 tively .anaerobic. It is not motile, is usually straight, 

 and has square ends, which are characteristic. In the 

 blood, where it occurs singly or in short chains, the ends 

 of the bacillus are slightly convex; on cultivation they 

 become slightly concave, but neither modification dispels 

 the characteristic squareness of appearance. Round and 

 oval involution forms are often seen in old and attenuated 

 cultures. In the fresh state the threads do not show 

 segmentation; this is seen only on staining. 



In cultures chains of great length are formed. When 

 the bacilli have a supply of oxygen, and the temperature 

 is between 20 and 38 C., ellipsoidal central spores are 

 developed. Spores are not found during life, being only 

 developed after death, when the bloody discharges come 

 in contact with air. A variety, first obtained by Behring, 

 which is sporeless for many generations, is produced by 

 culture at 42 C., or on nutrient gelatin containing 0-1 

 per cent, of phenol. 



Culture. On a gelatin plate small spherical colonies 

 develop in the depth, which consist of closely twisted 

 bands of bacillar chains. When the growth reaches the 



