.5 c.c. }
Glycerine 20.0 c.c. } and add to the stain.

~Method.~--

1. Place tissue in the above stain for ten minutes.

2. Differentiate and dehydrate with absolute alcohol.

3. Clear in xylol.

4. Mount in xylol balsam.

~To Demonstrate Capsules.~--

1. _MacConkey's Method._--Stain precisely as for cover-slip films
(_vide_ page 100).

2. _Friedlaender's Method._--

Stain.--

Gentian violet, saturated alcoholic solution 50 c.c.
Acetic acid, glacial 10 c.c.
Distilled water 100 c.c.

METHOD.--

1. Prepare the sections for staining, _secundum artem_.

2. Stain sections in the warm (e. g., in the hot
incubator) for twenty-four hours.

3. Wash with water.

4. Decolourise lightly with acetic acid, 1 per cent.

5. Dehydrate rapidly with absolute alcohol.

6. Clear with xylol.

7. Mount in xylol balsam.

~To Demonstrate Acid-fast Bacilli.~--

1. Prepare the sections for staining in the usual way.

2. Stain with haematin solution ten to twenty seconds, to obtain a pure
nuclear stain; then wash in water.

3. Stain with carbolic fuchsin twenty to thirty minutes at 47 deg. C.;
then wash in water.

4. Treat with aniline hydrochlorate, 2 per cent. aqueous solution, for
two to five seconds.

5. Decolourise in 75 per cent. alcohol till section appears free from
stain--fifteen to thirty minutes.

6. Dehydrate with absolute alcohol.

7. Clear very rapidly with xylol.

8. Mount in xylol balsam.

~To Demonstrate Spirochaetes in Tissues.~

~Piridin Method (Levaditi).~--

1. Cut slices of tissue 1 mm. thick.

2. Fix in 10 per cent. formalin solution for twenty-four hours.

3. Wash in water for one hour.

4. Place in 96 per cent. alcohol for twenty-four hours.

5. Measure into a dark green or amber bottle 100 c.c. silver nitrate
solution 1 per cent., and 10 grammes pyridin puriss. Transfer slices of
tissue to this. Stopper and keep at room temperature three hours, then
in thermostat at 50 deg. C. for four to six hours.

6. Wash quickly in 10 per cent. pyridin solution.

7. Reduce silver by transferring slices of tissue to following solution
for forty-eight hours.

Pyrogallic acid 4 grammes
Acetone 10 c.c.
Pyridin puriss 15 grammes
Distilled water 100 c.c.

8. Wash well in water.

Take through alcohols of increas