lO LABORATORY BACTERIOLOGY 



cloth and placed in the incubator until the next laboratory day. 

 Then carefully examine them, and if any of the tubes are con- 

 taminated, that is, if the liquid is clouded or has a membrane 

 on the surface, they must be rejected. Label all others, and 

 place them in the locker. 



13. Labelling Media and Culture Tubes. — Stick on each tube 

 of media, about 3 cm. from the top, an adhesive, white label 

 about 2 cm. square. On the upper line should be written the 

 name of the medium, and the date of its preparation. Thus, 

 Bouillon, 13-VII-1900. When the tube is used, the name of the 

 organism or material with which it is inoculated, together with 

 the date of inoculation, should be written on the lower lines. 

 This appUes to all media and tube or flask cultures. 



