42 General Bacteriology. 



e. Flood the cover- glasses thus prepared with the following solution (Mordant) : 

 Liquor ferri sesquichlorfdi diluted with distilled water 1:20, 1 part; saturated aqueous 

 solution of taunic acid, 3 parts. This mixture improves with age but should be filtered 

 before using. Allow to act 1 minute. 



/. Wash in water and dry between filter paper. 



g. Stain with hot carbol-fuchsin for about one minute. 



h. Wash in water, dry and mount in balsam. 



REFERENCES. M. & W. 103; McF. 104; P. 205. Other methods M. & R. 115; 

 McF. 101; A. 167. 



SPECIAL, DIRECTIONS. Stain B. typhi from cultures furnished, also try B. coli and 



B. subtilis. 



EXERCISE XXXVI. CAPSULE STAIN (Welch). 



GENERAL DIRECTIONS. 



a. Spread film without the use of water. 



b. Air dry. 



c. Fix. 



d. Apply glacial acetic acid, and drain it off immediately. Do not wash in water. 



e. Stain with anilin-oil gentian violet (Ehrlieh) which is to be renewed several 

 times to remove acid. 



/. Wash in 1 to 2% salt solution. 



g. Examine in salt solution. (Balsam causes capsule to shrink.) 

 REFERENCES. A. 163; P. 203; P. B. C. 13. 



SPECIAL DIRECTIONS. Use pneumonic ("rusty") sputum, or blood of rabbit in- 

 fected with the pneumococcus. 



