io8 LABORATORY GUIDE IN BACTERIOLOGY 



Cool three to 43, and inoculate while fluid. Let the 

 other three become solid, and make stab-cultures. 



b) Sterilize the cotton stoppers in a flame, and with 

 the forceps, sterilized in a flame, push the stoppers into 

 the test-tubes for the distance of about i inch (2-3 cm.). 



c) Pour into the tubes (upon the cotton stoppers) 

 2 c.c. of a saturated solution of pyrogallic acid in water, 

 followed by 2 c.c. of a 2 per cent, solution of NaOH. 



d) Cork the tubes immediately with rubber stoppers, 

 and keep upside down. 



e) Incubate at the required temperature. 



Upon what principle does this method depend ? 

 Do the organisms grow both aerobically and anaerobi- 

 cally ? 



When you have obtained a growth, stain the organ- 

 isms with anilin-gentian-violet and by Gram's method. 

 Describe and illustrate. 



3. Special study C. Cultivation by Buchner's 

 method, using fruit-jars. 



a) Into a Mason fruit-jar of ordinary type deposit 

 10 g. of pyrogallic acid. 



b) Smear vaselin around the mouth of the jar. 



c) Pour into the jar 100 c.c. of a i per cent, solution 

 of NaOH. 



d) Then deposit in the jar culture-tubes previously 

 inoculated. 



e) Tightly fasten the cover of the jar, and incubate 

 at 37 for 48-72 hours. 



4. Special study D. Cultivation in hydrogen gas. 



a) Inoculate all media from stock-cultures obtained. 



b) Fit up apparatus as shown in Fig. 34. 



c) Place culture-tubes in a Novy jar (Fig. 34, a). 



