26 General Bacteriology. 



In cases where vital movement is questionable, remove the cover-glass and place a 

 drop of formalin or chloroform in the bottom of the cell; replace the cover-glass, ex- 

 amine and note change in character of movement, if any. 



EXERCISE XX. TEST-TUBE CULTURES ILLUSTRATING FORM TYPES. 



a. Make test-tube cultures in bouillon, gelatin, agar and potato of the following 

 organisms : 



Micrococcus (any species). 



Sarcina lutea SCHROETEB. 



Pseudomonas fluoresce ns (FLUEGGE) MIG. 



Bacillus mycoides FLUEGGE. 



Microspira Metschnikovi MIG. (or any vibrio). 



Spirillum rubrum v. ESMARCH. 



6. Incubate all cultures, except gelatin, at 28 C. 



EXERCISE XXI. STUDY OF TEST-TUBE CULTURES. 



GENERAL DIRECTIONS. As soon as growth becomes visible a systematic and careful 

 study of the cultures should be made. A detailed list of the points to be noted will be 

 found in Chapter III, and should be consulted in writing up the descriptions. The sum- 

 mary below will, however, be found useful. 



For bouillon cultures note : 1) condition of fluid, 2) character of sediment, 3) pres- 

 ence or absence of membrane, and 4) characteristic odor. 



For solid cultures (agar and potato slopes), note: 1) Form of growth, 2) size, 3) 

 surface elevation, 4) consistency, 5) color, 6) effect on media, and 7) characteristic odor. 



For gelatin stab cultures, note: 1) Effect on media, a. non-liquefying, i) line of 

 puncture, ii) surface, b. liquefying, i) shape of liquefied area, ii) condition of fluid, iii) 

 character of sediment, 2) characteristic odor. 



The study should be continued from day to day as long as changes are noted. Make 

 drawings wherever they will be of service in elucidating the descriptions. 



REFERENCES. P. B. C. (Charts by Cheesman.) 



SPECIAL DIRECTIONS. Study and write careful descriptions and make necessary 

 drawings of all cultures made. 



EXERCISE XXII. MICROSCOPICAL STUDY OF FORH TYPES. 



a. Make cover-glass preparations from the agar streaks (XX) and stain with an 

 aqueous solution of gentian violet or with Loeffler's methylen blue. 



b. Examine with the oil-immersion objective, write the names of the organisms in 

 their proper place in the table below. 



Name. Sketch. 



( medium . 

 Coccaceae (spherical) 



(. small . . 



( large . 

 Bacteriaceae (elongated) 



( small . 



( curved- . 

 Spirillaceae (spiral) 



(. twisted . 



