Workshop on stains and staining

 Saturday 6th April 2024

The workshop in the Angela Marmont Centre in the Natural History Museum got off to an unusual start. Most of the stains that we would be using only need to be applied for a short period, but haematoxylin needs to be applied for at least an hour. Terry Hope provided slides with sections of rat stomach, so we started by either dipping the slides in haematoxylin, or applying a drop with a pipette.

Stains and equipmentStains and equipment

Nigel Williams applying haematoxylinNigel Williams applying haematoxylin

While the staining was left to work, Terry gave a talk on the history and uses of stains and staining.

Terry Hope’s introductory talkTerry Hope’s introductory talk


Terry brought a bag of flowers from his garden so that we could make slides of pollen. The mountant was glycerine jelly that contains basic fuchsin, and is easy to use. Basic fuchsin is a magenta stain. The jelly needs to be warm, so the jar was kept in a mug of warm water until it was needed. We used a small brush to transfer pollen onto a slide, then a glass rod to apply a drop of the jelly, and finally added a coverslip. The pollen gradually takes up the fuchsin from the jelly. Glycerine jelly does not set hard, and it is hygroscopic, so to make slides permanent they need to be ringed with nail varnish, shellac, or a commercial ringing cement.

Transferring pollen to a slideTransferring pollen to a slide

Adding glycerine jelly to pollen slideAdding glycerine jelly (with basic fuchsin) to pollen slide

Cheek cells

We were provided with smooth wooden spatulas for gently scraping the insides of our cheeks and then transferring the material to a slide. We dried the smears on the makeshift hotplate, then used a pipette to add a little methylene blue. Methylene blue is a blue stain that makes cell nuclei more visible. The methylene blue was left for about 2 minutes, and then washed off with water.

David and Rhodri Lewis adding methylene blue to cheek smearDavid and Rhodri Lewis adding methylene blue to cheek smear

The Quekett members who had intended to bring hotplates were unable to attend because of the train strikes, so Lisa Ashby improvised with two hot-water bottles and a thin metal sheet.

Makeshift hotplateMakeshift hotplate

Blood smears

Terry Hope pricked his thumb using a lancet to produce drops of blood. He showed us how to transfer a drop to the end of a slide, and then use a second slide to spread out the blood into a thin smear. We dried the slides, added some Giemsa stain, left it for 10–20 seconds, rinsed with alcohol, and then dried again. Giemsa stains red blood cells a different colour from white blood cells and platelets.

Rat stomach sections

Finally we returned to the sections of rat stomach that had been staining in haematoxylin since the start of the workshop. We rinsed off the excess stain with acid alcohol. Haematoxylin is red but can be turned to blue with alkaline, so we then rinsed the slides with an alkaline solution.

Bluing haematoxylin with alkaline rinseBluing haematoxylin with alkaline rinse

We then applied a second stain, eosin, and rinsed it off after  a few seconds. The blued haematoxylin stains the nuclei of cells a bluish colour, and the eosin stains cytoplasm a pinkish colour. The combination is often referred to as H&E stain.

Drying slidesDrying slides

We were then able to examine the slides under a microscope, with a 40× objective giving the best view.

Examining the slidesExamining the slides

Examining the slidesExamining the slides

Pollen grains stained with basic fuchsinPollen grains stained with basic fuchsin (20× objective) [photomicrographs by Pam Hamer]

Cheek cells stained with methylene blueCheek cells stained with methylene blue (20× objective) [photomicrograph by Pam Hamer]

Discussing the techniquesDiscussing the techniques

Stained slides and notesStained slides and notes


Some Quekett members brought gossip exhibits.

Lisa Ashby brought some slides of stained specimens from her collection

Prepared stained slidesPrepared stained slides

Lisa also brought some bits of an old pollen filter from her car, so that we could try to transfer the pollen to slides.

Nigel Ashby brought a copy of A History of Microtechnique by Brian Bracegirdle which contains an illustration of an apparatus for keeping embedding wax liquid, together with the version that he had constructed. A tin containing the wax sits on the wide end of a long, thin triangle of copper that is suspended above a baseboard. A spirit lamp placed below the narrow end provides the right amount of heat.

Wax warmerWax warmer

Nigel Williams brought an arrangement of butterfly scales by Klaus Kemp, and we were able to admire it using a stereomicroscope.

Nigel Williams’ exhibitNigel Williams’ exhibit

Butterfly scale star by Klaus KempButterfly scale star by Klaus Kemp [photomicrograph by Nigel Williams]

Pam Hamer showed some examples of staining non-biological material

Keith Abineri used to make peels of polished and etched rocks , and then stain the peels to help with identifying the minerals.

Stained rock peelsStained rock peels

Staining can also be used to monitor microplastics.  There are two recent paper on monitoring microplastics in water and sediment using Nile Red staining to produce fluorescence in the microplastics.

Nile Red for detecting microplasticsNile Red for detecting microplastics

Report and most photographs by Alan Wood

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