STAINING AND MODIFICATIONS. 39 



section is then taken, avoiding the errors, if any ; and having 

 reached this stage proceeded with as follows : 



Dish IV, alcohol, 2 to 3 seconds to remove the water in the 

 tissue. 



V. A few drops of oil of cloves, just long enough to clear the 

 specimen to make it transparent (so that an object placed under 

 neath will shine through). 



VI. Remove excess with filter-paper. 



VII. Mount in Canada balsam (xylol balsam). 



CHAPTER VI. 



SPECIAL METHODS OF STAINING AND MODIFICATIONS. 



Gram's Method of Double Staining. (For cover-glass speci- 

 mens.) I. A hot solution of anil, water gentian violet 2 to 10 

 minutes. 



II. Directly without washing, into Gram's solution of iod. 

 potass, iod. 1 to 3 min. (the cover-glass looks black). 



III. Wash in alcohol 60 per cent, until only a light brown 

 shade remains (as if the glass were smeared with dried blood). 



IV. Rinse off alcohol with water. 



V. Contrast color with either eosin, picro-carmine, or bismark- 

 brown. The bacteria will appear deep blue, all else red or brown 

 on a very faint brown background. 



The following bacteria do not retain their color with Gram's 

 method are therefore not available for the stain : Bacillus of 

 typhoid ; spirillum of cholera ; bacillus of chicken cholera, of 

 hemorrhagic septicaemia, of malignant redema, of pneumonia 

 (Friedlander), and of glanders; diplococcus of gonorrhoaa ; spi- 

 rillum of relapsing fever. 



Gram's Method for Tissues (modified by Giinther). 



I. Stain in anil, water gent, violet . . 1 minute. 

 II. Dry between filter paper. 



III. Iod. potass, iod. sol. .... 2 minutes. 



IV. Alcohol minute. 



V. 3 perct. sol. hydrochloric acid in alcohol 10 seconds. 



VI. Alcohol, ol. of cloves, and Canada balsam. 



