Ribosomes, or the particles of Palade

Early electron microscopy (EM) was troubled by, as George Palade put it, “the perennial and arduous question of artifact versus reality.” Stains and fixatives could precipitate—Keith Porter referred to this as “the coagulating action of the fixative”—and produce structures that were not present in the original sample.

But when Palade noted a particulate component of the cytoplasm, he confirmed its presence using two different fixatives, and described its particular abundance in embryonic, rapidly proliferating, and glandular cells (Palade, 1955). Thus were born the particles of Palade, later known as ribosomes.

Palade saw that the particles were both on the endoplasmic reticulum (ER) and free in the cytoplasm. Although the ER was identified in 1945 (Porter et al., 1945), by 1955 the terms ER, ergastoplasm, and basophilic cytoplasm were still used almost interchangeably—the last in reference to...