ABSTRACT
This chapter introduces the reader to the terminology, chemical natures, and some other properties of colored and otherwise visible or potentially visible substances. It points out difficulties in obtaining correctly labeled and sufficiently pure compounds, and addresses these problems. The purpose of staining is to add color to plant or animal tissues. This is done sometimes to increase the visibility of objects that can be seen with the unaided eye. The great majority of substances used in biological staining are dyes. Almost all dyes are organic compounds of the aromatic series and are therefore derivatives of benzene. The word colorant is applicable to any substance that is capable of coloring or staining a material. John Baker argued that this word should be the term of choice for biologists when referring to any substance that stains tissues. The chapter concludes with lists of some major books and journals that cover the large field of dyes, dyeing, biological staining and histochemistry.
