The first biological electron micrograph -- 1934

The first transmission electron micrograph of a biological specimen ever published is reproduced here. It represents a hand-cut section of sundew (Drosera sp.) leaf prepared by L. Martan, 1934, in Belgium.

Obviously, the image showed no useful structural information, but merely proved that imaging could occur with this type of instrument. It remained until techniques of fixation and ultra thin sectioning could be accomplished before useful detail could be shown in biological electron micrographs. That did not fully occur until the 1960's.

The transmission electron microscope is distinguished by:

using a high energy electron beam instead of visible light

using soft iron electromagnetic lenses instead of glass lenses

employing a high vacuum environment for the electron beam to travel without interruption

recording images onto photographic emulsion, or electronically, inside the vacuum chamber