Transmission electron micrograph of a thin section of plastic-embedded material from the 'rough microsome' fraction of a preparation of rat liver. Subsequent to this early image, 'microsomes' became known as ribosomes, and the subcellular fraction consisting of membrane fragments studded with ribosomes became termed rough endoplasmic reticulum, the site of synthesis of proteins destined for export from the cell.
Original 3.25 in. x 4 in. lantern slides were scanned at 600dpi.