Van Gieson's stain, as already given, may be used. The best results are obtained after fixation in chrome salts or sublimate solutions; are not so good after alcohol.

Mallory's anilin blue stain gives good results after fixation in Zenker's fluid or sublimate solutions. The fibrillae and reticulum of connective tissue, amyloid, mucous, and other hyaline substances stain blue; the connective tissue can be differentiated from the other substances by their form. Nuclei, protoplasm, fibroglia, fibrils, axis-cylinders, neuroglia fibers, and fibrin stain red; erythrocytes and myelin sheaths, yellow; elastic fibers, pale pink or yellow.

Sections are:

1. Stained in a 0.1 per cent, aqueous solution of acid fuchsin five or more minutes.

2. Transfer to the following solution and stain twenty minutes or more:

Anilin blue soluble in water (Grübler)..... 0.5 gm.

Orange G. (Grübler)..................... 2.0 "

Aqueous Solution Of Phosphomolybdic Acid

(1 per cent.).......................... 100. o c.c.

3. Wash and dehydrate in several changes of 95 per cent, alcohol.

4. Clear in xylol or in oil of origanum (Cretici).

5. Balsam.

Elastic Fiber Stain. Weigert's Stain For Elastic Fibers

It is best to buy the stain already made up, as its preparation is rather difficult. The sections are:

1. Stained in the above solution for twenty minutes to one hour.

2. Washed off in alcohol.

3. Blotted with filter-paper, xylol added, and blotted two or three times until the section is clear.

4. Mounted in balsam.

The elastic fibers are dark blue, almost black.

Unna's Orcein Stain

Orcein.................................... 1 gm.

Hydrochloric acid......................... 1 c.c.

Absolute alcohol.......................... 100 "

Sections are:

1. Stained six to twenty-four hours.

2. Washed thoroughly in 70 per cent, alcohol.

3. Washed in water to get rid of the acid.

4. Dehydrated, cleared, and mounted.

The elastic fibers are a deep silky brown color; connective tissue, a pale brown. This method has the advantage that elastic fibers that have degenerated into elacin take the basic blue stain.

Levaditi Stain For Treponema Pallidum

1. Fix small pieces of tissue, 1 to 2 mm. thick, in 10 per cent, formol for twenty-four hours.

2. Wash in water a few minutes; place in 95 per cent. alcohol for twenty-four hours.

3. Wash in distilled water until the tissue sinks.

4. Place in a 2 per cent, solution of silver nitrate and put in an incubator at 380 C. for three to five days. It is best to use amber-colored bottles.

5. Wash briefly in distilled water, then put in the following solution for twenty-four to forty-eight hours at room-temperature:

Pyrogallic acid........................... 3 gm.

Formalin................................. 5 c.c.

Aq. dest................................. 100 "

6. Wash in water, dehydrate, and embed in paraffin. The treponema will stain black; the rest of the tissue, yellow.

Kaiserling's Method Of Preserving Natural Colors In Tissues

1. Fixation for one to five days in -

Formaldehyd............................ 200 c.c.

Water.................................. 1000 c.c.

Nitrate of potassium..................... 15 gm.

Acetate of potassium..................... 30 "

Change the position of the specimen frequently. The time of fixation varies with the tissue or organ and the size of the specimen.

2. Drain and place in 80 per cent, alcohol one to six hours, and then in 95 per cent, alcohol for one to two hours, to restore the color.

3. Preserve in -

Acetate of potassium..................... 200 gm.

Glycerin................................. 400 c.c.

Water.................................. 2000 "

Exposure to light gradually affects the colors.