The Golgi apparatus was one of the first organelles to ever be discovered, primarily because its relatively large size enabled it to be visualized with a light microscope once a suitable staining technique was developed. This technique was a late 19th century innovation by the Italian physician Camillo Golgi. Golgi staining involves treating nervous tissue with silver nitrate and potassium dichromate. Initially much of the scientific community questioned whether or not the Golgi apparatus was an actual organelle. Many believed that what was being observed was simply a visual distortion resulting from the novel staining technique. The proximity of the Golgi apparatus (labeled with mEmerald fused to a Golgi targeting signal) to the endoplasmic reticulum (tagged with mCherry fused to an ER targeting signal) was visualized in the digital video sequences presented in this section.