 The introduction of new research techniques, especially cell fractionation and electron microscopy, figured centrally in the efforts to establish cell biology as a distinct discipline in the post-World War II period as they enabled constructing what Palade (1987) termed a bridge between morphological observations and biochemistry. Cell fractionation employs the ultracentrifuge to separate cell contents into fractions that contain the enzymes responsible for distinct cell activities while electron microscopy enables these fractions to be linked to organelles identifiable in cells. Matlin (2018) describes how Claude employed centrifugation to identify microsomes which exhibited high concentrations of RNA. Porter’s (1953) complementary micrographs of these particles in fractions and tissue slices (Figure 1) linked microsomes to the intracellular structure he had named the endoplasmic reticulum. As Matlin describes, this cycling between cell fractionation to establish function and electron microscopy to localize it to a structure was pursued repeatedly in cell biology.