1. =Sedimentation.= The formed elements of pathologic fluids (urine, sputum, pus, blood, exudates, transudates, cyst-contents, etc.) are examined by collecting the sediment of such fluids from the bottom of a sedimenting glass or bottle, by means of a capillary pipette controlled by the finger. While the sediment is passing up into the tube the pipette should be moved about the bottom of the vessel so as to get some of the sediment from all parts. When the fluid is rich in cellular elements sedimentation is not necessary; a drop of the fluid is placed upon the slide; if too thick it is diluted with physiologic salt-solution or serum. If poor in cellular elements the fluid must be centrifugalized by means of a water- or electric-centrifuge; and a drop of the sediment in the centrifuge tube is then removed by the pipette and placed upon the slide, and covered with a cover-glass. To facilitate the low-power examination of such sediments parallel streaks upon the slide may be made across its entire length, and examined without the use of cover-glasses. To apply the various reagents mentioned below it becomes necessary to use a cover-glass as directed. 2. =Smears.= A clean fresh cut is made into the organ or tissue, and a clean slide or cover-glass is drawn across the surface. Without permitting the smear to dry a drop of salt-solution or any desired reagent is put upon it, and it is then examined. This method is especially applicable to the study of the cells of the spleen, bone-marrow, lymphnodes, etc. Permanent balsam-mounts may be made of such smears by fixing with heat or alcohol and ether, staining, drying and mounting. 3. =Scraping.= A fresh cut is made into the organ or tissue, and the excess of blood absorbed by a pad of absorbent paper devoid of lint. A clean scalpel held at an angle of 45° is then drawn with some force back and forth over the cut-surface until its blade collects a sufficient amount of “tissue-juice” made up of the cells of the tissue. This is then put upon a slide, and covered with salt-solution or any desired reagent, and is then examined. This method is used especially for cellular infiltrations, soft tumors, and parenchymatous organs (spleen, lymphnodes, bone-marrow, liver, etc.), and for the inner wall of cysts (echinococcus-cysts, cysts lined with ciliated epithelium). 4. =Crushing.= A small bit of the tissue is cut out with the scissors or scalpel, and placed upon the slide. A cover-glass is then placed upon it and pressed down so firmly that the bit of tissue is spread out in a thin film or layer beneath the cover-glass. Reagents are introduced beneath the cover-glass, as desired. (See below.) This method is used in the examination of the lung, kidneys and brain for fatty embolism, and of the brain and spinal-cord for “fat-granule” cells, pigment, calcified ganglion-cells, Negri bodies, etc. It is also frequently used in the bacteriologic examination of tissues (crushing of tubercles, etc.).