PRINCIPLES OF VETERINARY SURGERY 109 



This is the regular staining solution, and a simple technique 

 is as follows : 



1. With a platinum loop spread a thin layer of the 

 specimen on a clean cover-glass. Dilute specimen with dis- 

 tilled water if too thick. 



2. Air-dry by allowing the cover-glass to remain in the 

 air until absolutely dry. 



3. Fix by passing cover-glass three times through a 

 Hame, either a Bunsen burner or alcohol lamp. 



4. Apply stain to the cover-glass and allow to remain 

 froni 3 to 5 minutes. 



5. Pour off stain and wash cover-glass in water to re- 

 move surplus stain. 



6. Dry cover-glass with filter paper; add a drop of 

 Canada balsam to the center of the stained side of the cover- 

 glass. 



7. Mount cover-glass on slide, turning the loaded slide 

 down. 



8. Label, add a drop of cedar oil, and examine under the 

 one-twelfth lens. 



The foregoing method can be used in the staining of 

 bacteria from culture media, or in the staining of pus, excre- 

 tions or secretions, or in the examination of any organ or 

 tissue for bacteria. Not only are the bacteria stained, but 

 the blood-cells and epithelial cells also. 



Examination of pus by this method would not only reveal 

 the character of the bacteria present, but also the nature of 

 the pus cells. In cold abscesses these would consist largely 

 of lymphocytes together with broken down tissue-cells ; 

 while in acute abscesses, the pus cells are mainly of the poly- 

 morphonuclear variety. This method will stain all bacteria 

 except the tubercle bacillus. ^i 



Tubercle bacilli do not take the ordinary stains, but 

 when once they do take a stain, they give it up with great 



