THE EXAMINATION OF MICRO-ORGANISMS 617 



(Heat a penny over the flame, remove it, place upon it the slide 

 witii spores and stain. Repeat several times.) 



(2) The Tetanus Bacillus. 



Short straight slender rod with rounded ends, slightly motile with 

 man^' flagella, forms spherical spores at one end, giving the " drum- 

 stick " appearance. Gram-positive. Not acid-fast. 



A strict anaerobe. Liquefies gelatin. In glucose-agar stab, a 

 feathery radiated growth with slight gas formation. Spores very 

 resistant. Nearly pure cultures obtained by heating ordinary earth to 

 80° C. on two to three successive days and then preparing agar shake 

 cultures. 



Produces two alkaloidal toxins, tetanotoxine and spasmotoxine, 

 which both produce convulsions. Readily destroyed by heat and light. 



Natives bury carcases in order to produce this toxin for arrow 

 poison. 



(3) The Bacillus oedematis maligni (Bacillus septicus). 



A motile slender rod (4 jx long), with several flagellce. Gram- 

 negative. 



Stains readily. Forms spores in a central position. Tends to grow 

 in long filaments. A strict anaerobe. Gelatin liquefied with pro- 

 duction of foul smelling gas. Blood serum liquefied. 



(4) The Bacillus botulinus. 



Large (4 to 6 /i), with rounded ends, slight motility, four to 

 eight flagella, forms terminal spores, an obligatory anaerobe. Gram- 

 positive. Does not curdle milk, ferments glucose with production of 

 acid and gas, lactose not fermented. In glucose gelatin yellowish- 

 brown translucent colonies are formed surrounded by a liquefied zone. 

 Causes botulism. 



(5) The Bacillus welchii. 



A long (3 to 6 jx'), thick bacillus in ones, chains and clumps, often 

 has a capsule, forms spores only in serum cultures, strictly anaerobic, 

 Gram-positive. Non-motile. Licjuefies gelatin slowly, produces gas 

 in dextrose and lactose, a honey-combed curd in milk with gas in 

 twenty-four hours. Cultures are stronglv acid. Found in septicaemic 

 and pyasmic infections of the gastro-intestinal tract. 



The important ones from the Coli Group are : — 



(i) Bacillus coli. 



(2) The capsulated bacilli." 



(3) The bacillus enteritidis group. 



(4) Bacillus typhosus. 



(5) Bacillus dysenteric. 



All are as a rule short, stout with rounded ends, form no spores. 



