The use of a reservoir of liquid to collect ribbons of thin sections as they are cut enables serial sections to be obtained and provides means for detecting variations in thickness. Reducing the effects of static friction and of external vibrations makes it possible to cut long series of sections 0.2&mgr; thick and uniform to better than five percent. Some observations which may throw some light on the mechanics of the cutting process are reported. Mounting the sections without any treatment is shown to be superior to any technique in which the embedding material is removed or replaced. It is shown that the technique provides sections in which a structural resolution of 200A is possible. The remaining artifacts introduced by the sectioning and mounting are easily recognized deformations which do not influence the interpretation.