Electron microscope observations on nucleolar structure. (Initial report)

Several morphological features of the nucleolus have been observed by the light microscope, although the majority of nucleoli appeared to be homogeneous masses. In the present experiment the periplasmodium nucleoli of Tradescantia reflexa have been observed with the aid of Shimazu magnetic electron microscope with an operating voltage of 50-140KV. In the central part of the metabolic nucleolus a lot of thread-substances are closely interwoven to one another. The peripheral part consists of a mass of fine threads giving the nucleolus a “honeycomb” appearance. There is no evidence of a limiting membrane surrounding the nucleoli.