EXAMINATION OF LIVING BACTERIA. 13 
(4) Draw by means of the camera the exact size 
of the bacteria to be measured. 
(c) Remove the slide of bacteria, and replace it 
with the stage micrometer. - 
(d) Over the figure of the bacteria now draw the 
scale of the stage micrometer, and read off directly 
the size of the bacteria in divisions of the stage 
micrometer. 
UI. EXAMINATION OF LIVING BACTERIA. 
1. Ordinary Examination. 
(a) Place a drop of water on a clean slide. 
(4) Pass the cotton plug of the tube containing 
the culture to be examined through the flame ; ex- 
Fic. 1.—Method of holding tubes during inoculation 
(McFarland). 
tinguish the ignited cotton by blowing or pinching 
out the flame. 
(c) Hold the test-tube containing the culture be- 
