84 STAINING TECHNIQUE 
II. Stain. 
Carbol fuchsin. 
III. Counter stain. 
Methylene blue. 
The smear is mordanted two minutes, washed in alcohol and water and 
then stained two to three minutes with gentle heat. It is then washed 
with water and remordanted again for two or three minutes. Counter- 
stain with methylene blue. 
Welch’s Method. Fix the smear in glacial acetic acid. After a 
few seconds pour off the acetic acid and flood with aniline gentian violet. 
Repeat until all acid is removed. Wash and examine. 
Huntoon’s MeEtTHop 
Preparation of Reagents. Solution 1. To be used as diluent. 
Three grams of nutrose are sifted into 100 c.c. of distilled water and 
heated to 100° C. in the Arnold sterilizer for an hour. Add 5 e.c. 
of a 2 per cent phenol solution to act as a preservative. Decant into 
a test tube and allow to settle. Employ the supernatant liquid as the 
diluent. (Since the supernatant liquid tends to become thinner by 
constant precipitation of the nutrose, the solution should occasionally 
be reboiled.) 
Solution 2. Fixing and staining solution. 
2 per cent aq. phenol solution . - . 100 c.c. 
Concentrated lactic acid . .......... 0.25 to 0.5 c.e. 
1 per cent acetic acid solution.......... ... lee. 
Saturated fuchsin in alcohol................ 1 ce. 
Carbol fuchsin, old solution. ... .......... 1 cc. 
This staining solution must be kept tightly corked. 
TECHNIQUE OF STAINING 
1. Employ the solution (No. 1) as a diluent emulsifying the bac- 
teria in 1 or 2 loopfuls and then spreading in as thin a film as possible 
with the loop. The use of the edge of a slide in spreading the film is 
not to be recommended. 
2. Allow to dry in the air. 
3. Cover the film with the fixative and the staining solution (No. 2) 
and allow to act for from 30 to 45 seconds. 
4. Wash quickly in water, dry and examine. 
