The first published electron micrograph of an animal cell (1945). In this whole mount of a chick embryonic fibroblast cultured on a plastic film, the thin cell margins permitted viewing of “filamentous mitochondria” as well as a “delicate lace-work extending throughout the cytoplasm” that porter later named the endoplasmic reticulum (ER). Magnification: X5600 [K. R. Porter et al., J. Exp. Med. 81:233.]