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, sterihzed 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 pyrogalUc 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. 



c) 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 pyrogaUic acid. 



b) Smear vaseUn 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). 



