Scanning Electron Microscopic Studies on Rabbit's Spinal Cord by Resin Cracking Method

Abstract

Small pieces cut from the spinal cord of the rabbit were fixed and dehydrated and embedded in gelatin capsules filled with Cemedine 1500. The Cemedine was hardened at -30°C and the capsules were cracked into two pieces. The cracked surface of the specimen was observed under the scanning electron microscope.1. In the cytoplasm of the anterior horn cell the Nissl bodies were observed like specks. The Nissl bodies were denser than the cytoplasm surrounding them and contained numerous granuies (about 400Å in diameter) and membranous structures oriented parallel to each other. In the cytoplasm corresponding to the Golgi regions many vesicles and cisternal and membranous structures could be seen. On the surface of nerve cell bodies small swollen terminations of axons, which seemed to be end-bulbs, were observed.2. The membranes consisting of myelin sheaths, which surrounded the axon as a whirlpool, were observed in three dimensions. The myelin sheath sometimes extended thinner processes which could be considered to be the cytoplasmic processes of the neuroglial cell.3. The cilia covering the ependymal cells of the central canal were fairly uniform in number (12-15) from cell to cell, and were arranged in a tuft for each cell. The surface was also rich in microvilli which formed various shapes.