46 



GENERAL BACTERIOLOGY 



d. With the loop place a drop of liquid agar so as to cover up 

 streak. 



e. Flame a hollow-ground slide and seal the cover glass to it. In- 

 cubate and later examine and sketch. 



Eeperences. Hill, Hanging Block, Jour. Med. Research, 1902, 

 2 ; 202. 



EXERCISE 24. STUDY OF INVOLUTION FORMS. 



a. Grow Bacillus subtilis (Ehrenb.) Mig. in bouillon, and also 

 in water containing 0.1% asparagin, 10% sugar, and by means 

 of stained cover-glass preparations compare the individual organ- 

 isms in each case in regard to their form and size. The degenerated 

 or involution forms are more apparent by staining. Draw several 

 cells illustrating a variety of involution forms. 



b. Examine a culture of Bacterium diphtheriae (Loepfler) Mig. 

 on LoefSer 's blood serum. Eead M. & R. 5. 



EXERCISE 25. STUDY OF ENDOSPORES. 



a. Make cultures on peptoneless agar, or on an agar tube to which 

 a few drops of calcium hydrate have been added, of the following 

 organisms and incubate at 28° or 38° C. : 



Bacillus subtilis (Ehrenb.) Cohn". 



Bacterium anthracis (Koch) Mig. (or Bacillus mycoides 

 Fluegge). 



Bacillus amylobacter Van Tieghem (or any Clostridium form) . 

 Bacillus tetani Nicolaier (or any "drumstick" bacillus). 



b. When the cultures are 48 hours old mount films without stain- 

 ing, examine and fill out following table : 



