48 GENERAL BACTERIOLOGY LESSON 



(5) Prepare gelatine streak cultures of the Staphylo- 

 coccus pyogenes aureus and cereus flavus respectively, and 

 keep them at 22 C. 



The former will liquefy the gelatine, the latter will 

 not. 



(6) Prepare two hanging drop cultures of the Strepto- 

 coccus pyogenes in the usual manner, and keep them at 

 38-5 C. 



(7) Prepare films from the condensation water of an agar- 

 agar culture of the Streptococcus pyogenes, and stain them 



(a) with gentian-violet, fuchsine, or Loffler's methy- 

 lene-blue ; 



(b) by Gram's method. 



Mount in xylol balsam and examine with a high 

 power, or -^ in- oil immersion. 



(8) Prepare specimens of the pus supplied which con- 

 tains Streptococci. The pus has been preserved in carbolic acid 



? (5 per cent solution). 



(a) With a platinum loop remove some of the white 

 sediment and place it on a clean cover-glass. 



(b) Place another cover-glass on this and rub the two 

 cover-glasses together so as to spread the films uniformly. 



(c) Separate the cover-glasses and allow the two films 

 to dry. 



(d) When dry, pass the films three times through the 

 flame. 



(e) Place the films in a mixture of alcohol and ether 

 (equal parts) for one to two minutes. 



