Gill hematoxylins: first person account

This is a personal and practical account of Gill hematoxylin, how it came to be, its composition, illustrations of its appearance in solution with subsequent additions of hematoxylin, oxidizing agent, mordant, a tabular history of relevant contributions, identification of the surface precipitate that forms on concentrated hematoxylin formulations (e.g., Harris), the role of acetic acid, the difference between progressive and regressive staining, differentiation, bluing, quality assurance using buccal smears, and troubleshooting. As a de facto case study, the information can be extrapolated to all other extant hematoxylin formulations and to a comprehensive approach to the implementation of all stains.