70 



Measure the tubercle bacteria in one of the preparations 

 and make a drawing showing a few of them magnified 1000 

 diameters. 



1 15. Making cover-glass preparations from sputum. 

 Select the little yellowish colored masses, if present, remove 

 them by means of the fine forceps or platinum loop, and 

 spread them on the cover-glass in a thin layer. If the sputum 

 is homogeneous make the preparations the same as from cul- 

 tures, using a small loopful of the liquid. If the sputum is 

 viscid it is necessary to use the forceps to spread the film on the 

 cover-glass. After drying, the films are fixed by passing 

 the preparations through the flame, after which they are 

 ready to be stained. 



116. Gabbett's method of staining tubercle bac- 

 teria. 



(1) The stain (carbol fuchsin) : 



Fuchsin, i gram. 



Absolute alchool, 10 c. c. 



5% carbolic acid 100 c. c. 



(2) The decolorizer and counter stain : 



Methylene-blue powder 2 grams. 



10% sulphuric acid, 100 c. c. 



Stain the preparation with the first solution as described 

 in ( 76) then rinse in water and stain one minute with 

 the second solution which decolorizes and counter stains at 

 the same time, and again rinse in water. If the film has a 

 bluish tint it is ready for examination, if not, it should be 

 stained a little longer in the second solution. In these prep- 

 arations the tubercle bacteria should appear as slender, more 

 or less curved, rod-shaped bodies of a deep reddish color while 

 the surrounding tissue and other bacteria present are stained 

 a more or less intense blue. 



