PRINCIPLES OF VETERINARY SURGERY 111 



1. Lugol's Solution or Gram's Solution: 



Iodine i gram 



Potassium Iodide 2 grams 



Water . 100 c.c. 



2. Aniline oil gentian-violet: 



Aniline water (2 c.c. of aniline oil to 50 c.c. of 



water — filter clear) 10 c.c. 



Gentian-violet (saturated alcoholic solution) . . i c.c. 



The aniline oil gentian-violet should be prepared just 

 before using, as the solution does not keep. The various 

 steps in using Gram's method are as follows : 



1. Spread a thin layer on the cover-glass or slide. 



2. Air-dry. 



3. Fix in a flame. 



4. Stain with aniline oil gentian-violet 5 minutes. 



5. Pour o& stain and wash in water. 



6. Apply Lugol's solution 2 minutes. 



7. Wash freely in alcohol until no more color is given 

 o&. 



8. Wash in water, dry, and mount in Canada balsam. 



9. Examine with the oil-immersion lens. 



Eosin or Bismark-brown can be used as contrast stains 

 for the bacteria which are decolorized by this process of 

 staining. After washing in water (step 8), apply either 

 eosin or Bismark-brown for one minute, wash in water 

 again, and mount, etc. 



The bacteria "taking" the Gram stain are of a deep pur- 

 ple color; those "refusing," are colored pink or brown, ac- 

 cording to the counterstain used — eosin or Bismark-brown. 



SURGICAL BACTERIA.— Nearly all of the pathogenic 

 micro-organisms might, on some pretext or other, be classi- 

 fied with the so-called "surgical bacteria." Most all bacteria 

 are capable of entering the body through the avenue opened 

 up by the accidental or the surgical wound, which fact alone 

 greatly enlarges the scope of surgical bacteriology. But 



