AGAR PLATES FROM PUS. 25 



abscess) on a cover glass, dropping upon this a second 

 cover glass and sliding the two apart. 



(b) Dry and fix by passing through the flame. 



(c) Stain these films, 



(1) with eosin and methylene blue (page 21); 



(2) with diluted gentian violet; 



( 3 ) by Gram's method and eosin (page 18). 



Agar Plates from Pus. 



5. (a) Liquefy two agar tubes by heating to 1(X)°C. 

 for several minutes. Permit these tubes to cool in 

 water. (Agar sets at 38°0.) 



(b) Inoculate a few cc. of sterile water or a broth 

 tube with two loops of the pus furnished. 



(c) When the agar tubes have cooled to 42°C. rapidly 

 inoculate a tube with three loops from the inoculated 

 water or broth tube. 



(d) From this tube inoculate the second tube, using 

 three loops. Place the tubes in water at 42°C. 



Sterilize the tops of the tubes, and when cooled pour 

 into Petri dishes in the same manner as described in 

 making gelatine plates. 



Incubate at 37°C., examining after 24 and 48 hours. 



The use of plates in ordinary practice is not neces- 

 sary, as tubes can be smeared either directly from the 

 pus, using minute amounts, or better, can be smeared 

 from the dilution in sterile water or broth. 



