98 LABORATORY BACTERIOLOGY 



EXERCISE XL 



BACILLUS TETANI 



143. The bacilli of tetanus or their spores occur in nature as 

 common inhabitants of the soil at least they are found in the 



'soil in certain localities. They are believed to be more numer- 

 ous in certain places where manure has been thrown in abun- 

 dance. Bacillus tetani is anaerobic and consequently must be 

 cultivated according to methods necessary for such bacteria 

 ( 141, 142). In its effect upon the animal body it remains 

 at the point of inoculation, the disease being produced by 

 the toxin elaborated by the bacilli. 



REFERENCES. See text-books. Kitasato, Zeit. f. Hygiene, 

 Bd. X., S. 267. Wesbrook, Jour. Path, and Bact, Vol. Ill, p. 70. 

 Kanthack (morphology), Ibid., Vol. IV, p. 452. Vaillard and 

 Rouget "(etiology), Ann. de 1'Inst. Pasteur, T. VII, p. 755. 



144. Work for this exercise. Carefully examine the 2 cul- 

 tures of tetanus bacilli made in the last exercise and describe 

 their appearance. 



Make 2 cover-glass preparations from the liquid culture 

 and stain them with carbol fuchsin. Examine them micro- 

 scopically and describe their appearance. Make a drawing of 

 a few bacilli magnified 1000 diameters. Keep these cultures 

 until the next exercise, when they should be reexamined, 

 sterilized, and rejected. 



Inoculate a tube of each medium in Groups A and B with 

 Bacterium anthracis from a culture furnished for study at the 

 next exercise. 



145. Method of isolating tetanus bacilli. Tetanus bacilli 

 rarely extend beyond the place of inoculation into the body 

 of the infected individual (man or lower animal). In the 

 local lesion there are almost always other bacteria, so that 



