BNL STEM specimen example:   Freeze-dried Earthworm Hemoglobin.

A freeze-dried preparation of hemoglobin from the common earthworm is shown in this full-size image from STEM-1. Most of the views are end-on, showing in some cases a central cavity and suggesting six-fold symmetry. The straight rods are Tobacco Mosaic Virus (TMV) particles which are used as internal control in most STEM specimens. The full scale of the dark-field micrograph is 0.512 microns.