When the examination of drugs is a daily occurrence, the above method will be found highly satisfactory. MACHINE MICROTOMES When a number of sections are to be prepared from a given specimen, it is desirable to cut the sections on a machine microtome, particularly when the sections are to be prepared for the use of students, in which case they should be as uniform as possible. Great care should be exercised in cutting sections with a machine microtome--first, in the selection of the type of the microtome; and secondly, in the style of knife used in cutting. For soft tissues embedded in paraffin or collodion, the =rotary microtome= with vertical knife will give best results. The thickness of the specimen is regulated by mechanical means, so that in cutting the sections it is only necessary to turn a crank and remove the specimens from the knife-edge, unless there is a ribbon-carrier attachment. If the sections are being cut from a specimen embedded by the quick paraffin method, it is best to drop the section in a metal cup partly filled with warm water. This will cause the paraffin to straighten out, and the specimen will uncoil. After sufficient specimens have been cut, the cup should be placed in a boiling-water bath until the paraffin surrounding the sections melts and floats on the water. Before removing the specimen from the water-bath, it is advisable to shake the glass vigorously in order to cause as many specimens as possible to settle to the bottom of the cup. The cup is then placed in iced water or set aside until the paraffin has solidified. The cake-like mass is then removed from the cup, and the sections adhering to its under surface are removed by lifting them carefully off with the flat side of the knife and transferring them, together with the sections at the bottom of the cup, to a wide-mouth bottle, and covered with alcohol, glycerine, and water mixture; or if it is desired to stain the specimens, they should be placed in a weak alcoholic solution. Specimens having a hard, woody texture should be cut on a =sliding microtome= by means of a special wood knife, which is especially tempered to cut woody substances. Woody roots, wood, or thick bark may be cut readily on this microtome when they have been embedded by the quick paraffin process. The knife in the sliding microtome is placed in a horizontal position, slanting so that the knife-edge is drawn gradually across the specimen. After cutting, the sections are treated as described above. The thickness of the sections is regulated by mechanical means. After a section has been cut, the block containing the specimen is raised by turning a thumb-screw. In this microtome the knife, as in the rotary type, is fixed, and the block containing the specimen is movable. If the specimen has been infiltrated with, and embedded in, paraffin or collodion, the treatment of the sections after cutting should be different.