With improved microscope and preparation techniques, studies of histo logical structures of plant organisms experienced a revival of interest at the end of the 19th century. From that time, histological data have sub stantially studies of the pioneers in botanical science. From the beginning of the 20th century, the microscope allowed research in cell structure, the general functional unit of living beings. Advances in cytology gradually influenced histology, at first, however, rather timidly. Only the new and spectacular progress in ultrastructural cytology and cytochemistry led to a great...