Abstract
For the histochemical demonstration of sensitive enzymes it is necessary to use fresh unfixed tissue sections. With the following procedure one can constantly obtain such sections 10-20μ thick with relative ease. Schanze's sliding microtome is employed. The microtome knife is deeply cooled by placing blocks of dry ice on its surface, and is provided with a device for preventing the sections from rolling up. The microtome is operated in an ordinary refrigerator maintained at a temperature of 0-3°C. For this purpose, the door of the refrigerator is replaced by a wooden door provided with a glass window, gloved arm holes, and a small door.