42 General Bacteriology. 
e. Flood the cover-glasses thus prepared with the following solution (Mordant) : 
Liquor ferri sesquichloridi diluted with distilled water 1:20, 1 part; saturated aqueous 
solution of tannic acid, 3 parts. This mixture improves with age but should be filtered 
before using. Allow to act 1 minute. 
Jf. 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. 108; McF. 104; P. 205. Other methods M. & R. 115; 
McF. 101; A. 167. 
SPECIAL Directions. Stain B. typhi from cultures furnished, also try B. colé 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. 
¢. Stain with anilin-oil gentian violet (Ehrlich) which is to be renewed several 
times to remove acid. 
f. Wash in 1 to 2% salt solution. 
g. Examinein 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. 
