Abstract
Dye chemistry facilitated important advances in several scientific areas, as is the case of histology. In this field dyes are used to record images of biological tissues and cell anatomy under the light microscope. Besides that, the related science of Histochemistry addresses the understanding of the chemical composition and reaction mechanisms taking place in biological tissues. In Spain Santiago Ramón y Cajal, well known by his crucial contributions to the current knowledge of the nervous system, was also a leading innovator of staining methods for neurohistology, inaugurating a tradition of noted Spanish histochemists.