74 



MICROSCOPICAL EXAMINATION OF BACTERIA 



lively with Canada balsam dissolved in xylol, and sterile 

 vaseline. 



METHODS OF EXAMINATION. 



Bacteria, etc., are examined microscopically. 



1. In the living state, unstained, or stained. 



2. In the "fixed" condition (i. e., fixed, killed, 

 and stained by suitable methods) . 



The preparation of a specimen from a tube cultiva- 

 tion for examination by these methods may be de- 

 scribed as follows : 



1. Living, Unstained. (a) "Fresh" Preparation. 

 i. Clean and dry a 3 by i glass slip and place it on 

 one of the squares of filter paper. Deposit a drop of 

 water (preferably distilled) or a drop of i per cent, 

 solution of caustic potash, on the centre of the slip, 

 by means of the platinum loop . 



* Q 



K * 



U < 

 W 



FIG. 68. Holding tubes for removing bacterial growth, 

 as seen from the front. 



2. Remove the tube cultivation from its 

 rack or jar with the left hand and ignite the 

 cotton-wool plug by holding it to the flame of 

 the Bunsen burner. Extinguish the flame by 

 blowing on the plug, whilst rotating the tube 

 on its long axis, its mouth directed vertically 

 upward, between the thumb and fingers. (This 

 operation is termed "flaming the plug," and is 



