72 



with an aqueous solution of methyl-violet. Describe the 

 bacteria and make a drawing of a few of them. Preserve 

 one preparation. Keep the cultures and re-examine them 

 at each of the three following exercises. Note especially 

 the character and color of the growth on the potato. 



EXERCISE XLI. 



ACTINOMYCOSIS. 



§122. Explanatory note. Although actinomycosis is not 

 a bacterial disease, it is of peculiar interest as it is caused 

 by a fungus (ray fungus) of higher rank than bacteria. It 

 occurs in man and certain of the lower animals. The ray 

 fungus can be cultivated on glycerine agar and certain other 

 media but ordinarily it can be easily detected in fresh or 

 stained preparations of the affected tissue. 



§ 123. General directions. Examine a culture of 

 actinomycosis furnished and describe its appearance. Make 

 a hanging drop and a stained cover-glass preparation from 

 it. Examine and make a drawing of the fungus. 



Examine sections (which will be furnished) of animal 

 tissues containing the ray-fungus and also permanent prepa- 

 rations of the fungus isolated by maceration from actinomy- 

 cotic tissue. 



Inoculate a set of media with Bacterium anthracis for 

 studying at the next exercise. 



EXERCISE XEII. 



BACTERIUM (BACILI.US) ANTHRACIS. 



§ 124. General directions. Examine and describe each 

 of the cultures of this organism inoculated in the last 

 Exercise. 



