Take a clean cover-glass, smear one-half with normal blood, the other half with diabetic blood. Fix for 2 hours at 120°C., or in equal parts of absolute alcohol and ether at 60°C. for 4 minutes. Stain in a 10 per cent watery methylene-blue for 2 minutes, wash off the stain in water, and stain for 10 seconds in a ⅛ per cent watery eosin. Wash, dry and mount in balsam. In diabetic blood the red cells are green; in normal blood red. While this reaction is constant in diabetic blood it also occurs in leukæmia, Hodgkin’s disease, exophthalmic goitre and multiple neuritis. A 1 per cent solution of _Biebrich scarlet_ stains diabetic blood intensely, normal blood but slightly. On the other hand, a _1 per cent methylene-blue_ and a _1 per cent Congo red_ stain normal blood intensely and diabetic blood slightly. Staining of Glycogen in Leukocytes. To a solution of Lugol’s (100:3:1) add sufficient gum arabic to make a syrupy mixture. Keep tightly corked. Place a drop of this solution upon an air-dried film. After 1 minute dry with blotting paper. Examine with oil immersion. A positive reaction is shown by the presence of a diffuse brown or reddish-brown coloration or granules in the cell-body of the polymorphonuclear leukocytes. Staining of Fat in Blood. Stain in solutions of scharlach R or sudan III in 70 per cent alcohol. Staining of Blood-parasites. The _malarial parasites_, _trypanosomes_, _Leishman-Donovan bodies_, _sporidia_, _piroplasma bigeminum_, _spirilla_ and _spirochætes_ and the _filaria_ may all be stained with Wright’s or Giemsa’s modification of the Romanowsky method, or by any of the modifications of this method. (See also Staining of Animal Parasites.) _B. SECTIONS._ The blood is allowed to drop directly into Flemming’s solution and allowed to stand for 24 hours. It is then washed in water by repeated decanting, or the coagulum may be placed in a bottle covered with muslin, and then exposed to running water. It is after-hardened in alcohol and imbedded in paraffin. Safranin should be used to stain the sections. This method is especially good for the demonstration of mitoses in the blood-cells. Bone-marrow. Prepare films and fix and stain, as for blood films. For sections, fix the marrow in formol-Müller’s, mercuric chloride, Zenker’s, etc.; imbed in paraffin; cut very thin sections; stain with Ehrlich’s triple stain or Wright’s modification of Leishman’s stain. To distinguish the young forms of erythrocytes and leukocytes _Trambusi_ fixes in Flemming’s, stains the sections in a 1 per cent thionin solution in aniline-water (4:100), differentiates in acid-alcohol, and then brings the sections into a watery eosin and finally an alcoholic eosin, and mounts in xylol-balsam. Spleen and Lymphnodes.