1. =BLOOD.= Fresh spots should be scraped off and examined in physiologic salt solution. Older spots are scraped off when possible, or if the spots are on clothing or other fabrics, a piece of the stained portion is cut out, and the scraping or piece of material is placed on a slide in a macerating fluid (30 per cent caustic potash; glycerin 3 parts and concentrated sulphuric acid 1 part; 15 per cent tartaric acid; equal parts alcohol and ether; or Pacini’s fluid [mercuric chloride 1 grm., sodium chloride 2.0 grm., glycerin 100 cc., water 300 cc.]). Even in very old clots or stains some red cells may retain their characteristic form. The process of maceration should be observed directly under the microscope, as the macerating fluid gradually changes the cells after they become loosened. _Schmorl_ advises the following method:— Moisten a small piece of the fabric in water and stain with hæmatoxylin. Differentiate in acid alcohol, wash thoroughly in water, stain with 1/1000 watery eosin solution, wash in water (3-6 hours), place in alcohol, and then again in water. Tease with great care into fine threads on the slide, and examine the isolated fibres in a drop of glycerin. The red corpuscles are easily recognized; and the nuclei of the white cells or of the red cells of birds and amphibia stand out distinctly. Permanent mounts may be made by passing the specimen through alcohol, xylol, and mounting in balsam. A portion of the stained fabric may be imbedded in celloidin, sections cut, and stained with hæmatoxylin and eosin.