In the case of paraffin, the sections are fastened directly to the slide, and the paraffin is dissolved by either chloroform or xylol. The specimen is then placed in 100, 95, and 45 per cent alcohol, and then washed in water. These sections are now stained with water-stains, brought back through alcohol, cleared, and mounted in Canada balsam. If alcoholic stains are used, it will not be necessary to dehydrate before staining, and the dehydration after staining will also be eliminated. Sections infiltrated with collodion are either stained directly without removing the collodion or after removal. FORMS OF MICROTOMES The =hand cylinder microtome= (Fig. 34) consists of a cylindrical body. The clamp for holding the specimen is near the top below the cutting surface. At the lower end is attached a micrometer screw with a divided milled head. When moved forward one division, the specimen is raised 0.01 mm. This micrometer screw has an upward movement of 10 mm. The cutting surface consists of a cylindrical glass ring. [Illustration: FIG. 34.--Hand Cylinder Microtome] [Illustration: FIG. 35.--Hand Table Microtome] The =hand table microtome= (Fig. 35) is provided with a clamp, by which it may be attached to the edge of a table or desk. The cutting surface consists of two separated but parallel glass benches. The object is held by a clamp and is raised by a micrometer screw, which, when moved through one division by turning the divided head, raises the specimen 0.01 mm. The =sliding microtome= has a track of 250 mm. The object is held by a clamp and its height regulated by hand. The disk regulating the micrometer screw is divided into one hundred parts. When this is turned through one division, the object is raised 0.005 mm. or 5 microns, at the same time a clock-spring in contact with teeth registers by a clicking sound. If the disk is turned through two divisions, there will be two clicks, etc. In this way is regulated the thickness of the sections cut. When the micrometer screw has been turned through the one hundred divisions, it must be unscrewed, the specimen raised, and the steps of the process repeated. The knife is movable and is drawn across the specimen in making sections. [Illustration: FIG. 36.--Base Sledge Microtome] The =base sledge microtome= (Fig. 36) has a heavy iron base which supports a sliding-way on which the object-carrier moves. The object-carrier is mounted on a solid mass of metal, and is provided with a clamp for holding the object. The object is raised by turning a knob which, when turned once, raises the specimen one to twenty microns, according to how the feeding mechanism is set. Sections thicker than twenty microns may be obtained by turning the knob two or more times. The knife is fixed and is supported by two pillars, the base of which may be moved forward or backward in such a manner that the knife can be arranged with an oblique or right-angled cutting surface.