| Azur II—Eosin | 3.0 | grm. |
| Azur II | 0.8 | grm. |
| Glycerin (Merck’s pure) | 250.0 | cc. |
| Methyl-alcohol (Kahlbaum I) | 250.0 | cc. |
To 1 cc. of distilled water in a small, perfectly clean graduate add 1 drop of the stain, shaking very gently. Make very thin film; dry in air; fix 15-20 minutes in absolute alcohol. Cover preparation with a thin layer of the freshly diluted stain for 10-15 minutes, renewing stain at end of 10 minutes. Wash in a stream of water. Differentiate over-stained preparations in distilled water. Dry with absorbent paper; mount in balsam. Stains the spirochæte pallida and malarial organisms. The Giemsa solution may be obtained from Grübler. A more intense staining can be obtained by adding to the water used for diluting the stain 1-2 drops of a 0.1 per cent solution of potassium carbonate.
5. SPECIAL ELECTIVE STAINS FOR THE BLOOD.
1. Ehrlich’s Triple Stain.
| Saturated watery solution of Orange G | 120 | cc. |
| Saturated watery solution of acid fuchsin | 80 | cc. |
| Saturated watery solution of methyl green | 100 | cc. |
| Glycerin | 50 | cc. |
| Distilled water | 300 | cc. |
| Absolute alcohol | 180 | cc. |
Mix gradually; allow to stand for several months; do not shake or filter. Remove stain with pipette. Fix by heat, or pure methyl alcohol for 5 minutes. Stain 5-10 minutes; wash thoroughly, dry and mount in balsam. Neutrophile granules violet; eosinophile, a bright red; nuclei of the neutrophilic and eosinophilic cells greenish-blue; nuclei of the lymphocytes deep-blue; nuclei of the large mononuclears pale blue; those of red cells intense blue; red cells copper red. The Aronson-Philipp modification is more variable and less satisfactory.
Pappenheim’s Stain for Lymphocytes.
3-4 parts of polychrome methylene-blue or methyl green to 1-2 parts of pyronin. Fix in absolute alcohol. Nuclei blue-green; protoplasm bright red.
Staining of Blood-platelets.
The blood-platelets may be examined in the fresh state by coating a cover-slip with Deetjen’s agar-solution (boil 5 grms. agar-agar in 500 cc. distilled water, filter hot, and to each 100 cc. of the filtrate add 0.6 grm. sodium chloride, 6-8 cc. of a 10 per cent solution of sodium phosphate and 5 cc. of a 10 per cent solution of sodium diphosphate). Place drop of blood on this coating and examine on warm stage. For permanent stained preparations bleed into a fixing and staining fluid (equal parts alcohol and ether and Romanowsky’s stain) or use Wright’s stain.