A SIMPLE TUMBLING DEVICE USED IN PREPARING ALGAL SPECIMENS FOR ELECTRON MICROSCOPY

Screw cap vials are held in a wooden holder which rotates at a 90° angle to the horizontal. The. shaft of a small electric motor with built-in gear box is attached perpendicularly to the wooden vial holder via a hole drilled in the center of the wooden holder. The rotation of the vial holder is about 6 rpm. This motion ensures a thorough tumbling of the contents of the vials. Even viscous embedding media are kept in constant agitation, which provides for superior penetration of the tissue. Tumbling devices to hold a range of vial sizes can be constructed with a minimum of labor at a cost of $10-20 each.