Weigert advised the use of two stock solutions, I (absolute alcohol 33 cc., aniline oil 9 cc., methyl violet in excess) and II (saturated water solution of methyl violet). These solutions will keep for years. When ready to use stain take 3 cc. of Sol. I and 27 cc. of Sol. II. This staining mixture will keep for about 2 weeks. 1. Fix in alcohol, formol, acetone, mercuric chloride or Müller’s. Imbed in celloidin or paraffin; the latter preferably. Mount sections on cover-glass with albumin fixative. Celloidin sections must be fastened to slide by thin film of celloidin to prevent shrinkage. Sections fixed in chromic mixtures (and sometimes after formol fixation) must be oxidized in potassium permanganate and then reduced in oxalic acid to give good results. (Transfer sections to a 1 per cent solution of potassium permanganate to which 2 volumes of water have been added; oxidize for 10 minutes; then wash in water, and reduce for several hours in a 5 per cent water oxalic acid solution.) 2. Wash in water. 3. Stain in lithium carmine; differentiate in acid alcohol; wash thoroughly in water. 4. Stain on the slide or cover-glass in the aniline-methyl-violet (or gentian-violet) solution for 10 minutes. Wash off stain with physiologic salt solution. 5. Blot section with absorbent paper. 6. Cover section with Lugol’s (300-2-1) or a 5 per cent watery potassium iodide saturated with iodine. Leave on section for 1-5 minutes. 7. Blot off iodine. 8. Differentiate in aniline xylol (equal parts of xylol and aniline oil) until the nuclei become red. 9. Wash in xylol, blotting with absorbent paper. Repeat until section is transparent; then mount in balsam. All aniline oil must be removed before using the balsam. Nuclei are red; fibrin deep blue; bacteria, mucin, keratin and Altmann’s granules also blue. The differentiation must be carefully controlled under the microscope, and should be stopped before the finest threads of fibrin begin to be decolorized. =XI. GLYCOGEN.= Glycogen is soluble in water; and fixation and hardening must be carried out with absolute alcohol to prevent the solution of the glycogen. Tissue must be fixed immediately after death, as glycogen is quickly broken up. Its reaction with iodine is similar to that of amyloid, but it does not give the iodine-sulphuric-acid reaction that the latter substance does. 1. =Best’s Iodine Method.= 1. Fix and harden in absolute alcohol; imbed in paraffin; cut. 2. Stain somewhat deeply with hæmatoxylin. 3. Wash in water. 4. Stain in iodine 1, potassium iodide 2, water 100. 5. Dehydrate in iodine 2, absolute alcohol 100. 6. Differentiate in origanum oil, 1-2 hours. 7. Wash thoroughly with xylol. 8. Arrange on slide and dry in air. 9. Mount in pure melted balsam (no xylol). Nuclei are blue, glycogen brown.