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. Bremer’s Diabetic Reaction.