Since CORTI (1774) observed for the first time a streaming in plant cells, a history oJ mnre than 180 years has already elapsed in the study of proto- plasmic streaming. Durling this period of time, many experiments have been conducted and various discussions have been made nn prntoplasmic streaming, each of them within the limits of the knowledge and techniques of its own times and mnre or less under the influence of the ideas that pre- vailed then. With such a long history of research, in spite of all the interest and efforts that have been devoted to it by many, the mechani'sm of this in- triguing and complicated binlogical phenomenon is still left far from clear. It is an undeniable fact that one important factor stood in the way in analysing this phenomenon, that is, the limitations in the techniques ap- plicable to thi, s research. Another factor lay in the fact that we still have not enough knowledge about the protoplasm regar1ding its structural organisation, mechanochemistry, energetics, rheology, etc., all of which con- stitute basic problems in understanding the nature of the streaming.