PLATE-CULTIVATIONS. 7 9 



ose, or a platinum needle bent at the extremity 

 into a miniature hook, is held like a pen, and the 

 hand steadied by resting- the little finger on the 

 stage of the microscope. The extremity of the needle 

 is steadily directed to the space between the lens 

 and the gelatine without touching the latter, until, 



FIG. 29. MICROSCOPICAL EXAMINATION OF COLONIES ON PLATE- 

 CULTIVATIONS, AND METHOD OF ISOLATING COLONIES BY 

 INOCULATION OF TEST-TUBES. 



on looking through the microscope, it can be seen 

 in the field, above or by the side of the colony under 

 examination (Fig. 29). The needle is then dipped 

 into the colony, steadily raised, and withdrawn. 

 Without removing the eye from the microscope 

 this manipulation can be seen to be successful by 

 the colony being disorganised or completely re- 



