Intangible heritage at the university: making histological slides

Preparaten_Coloured slides_(c) ETWIE


Intangible cultural heritage is literally everywhere. It’s the practices, expressions, knowledge and skills that communities, groups and individuals recognize as part of their cultural heritage. These practices and know-how are transmitted from generation to generation, are created and transformed continuously by them, depending on the environment and their interaction with nature and history.

The UNESCO 2003 Convention for the Safeguarding of Intangible Cultural Heritage is a treaty adopted in 2003, enforced in 2006 and currently ratified, approved or accepted by 180 (of 193) states. The Convention wants to raise awareness at local, national and international levels of the importance of ICH.

At the university, those skills and practices are numerous. But often defined as tradition or just work, it’s not always future proof. What happens if the last taxidermist at the university collections is retired? Would student life be the same without the rituals at the beginning of the academic year or without a cantus? How will researchers do their biological research if there are no lab technicians who can provide detailed slides of the parts of the animals of plants they need, a skill which takes many years to perfect? What about the ceremoniously doctoral defences, or the wearing of the toga and hat at the end of your studies? What if there were no glass instrument makers that can have the skill to handcraft the ideas and designs researchers come up with for specific experiments? Quite a few people at universities are involved with more intangible cultural heritage than you (or they themselves) might think at first sight!

We want you to show an example of what ICH at the university is: the making of microscopic slides.


But first, some explanation about the technique. From an animal to histological slides: there are a few steps to follow. This is a short overview.

1. Fixation

After cutting out the piece of the octopus needed, fixation follows. That means treating it with chemicals and ensures that the tissue can no longer change or degrade. The fresher a tissue is, the better. The tissue is then placed in the histokinette. This device ensures that the tissue is drained of water as much as possible, and that it is fixed. Therefore, formol is used, to make sure that every part of the tissue becomes equally soft (or hard). The piece of octopus is secured in a tube and immersed in a carousel of different alcohol baths to gradually dewater.

Preparaten_Histokinette for fixation of the tissue (c) ETWIE

2. Embedding

Once the tissue is fully impregnated, it’s ready to be embedded. Usually paraffin, epoxy or another polymer is used. The choise of embedding depends on what result the researcher want and the experience of the lab technician. The embedding agent must fully penetrate the tissue, to achieve an optimal result of the sections.

Preparaten_Embedded mouth of an octopus (c) ETWIE

3. Slicing

When the tissue is embed, it has to be mounted to the holder of the microtome. This device with a sharp steel knife is used to cut very thin slices (‘sections’) of a block of tissue. The lab technician chooses the thickness of the sections and other parameters. Most common for histological work and the average microscope are sections of 2 to 10 micrometres. When the knife has cut a section, it is picked up with tweezers and put in a bowl of warm water to literally stretch out. The warm water makes the section spread out nicely and visibly. It is then fished up with the glass slide and placed on a heating plate to dry.

Preparaten_Slicing the tissues (c) ETWIE

4. Colouring

The sections are stained so that the cells can be seen more clearly. They are immersed in one or more colouring baths and put on the heating plate to dry before the coverslip can be applied. The slides have to dry for a few days to allow the glue to harden.

Preparaten_Colouring the slides_(c) ETWIE


Participatory documenting needs time and effort of course. In short, this is how we have done it.

  • Visit the lab technician, who shows and explained the technique;

  • Read about the technique, so you know the process and the different steps of the technique;

  • Interview with the practitioner, with the lab technician in this case;

  • Film the different steps of the process;

  • After editing, involve the lab technician to have some feedback and consent about the short film.

Filming the whole process (c) ETWIE


Our goal was to show two aspects in the short film. On the one hand, it had to show the different steps of the process of making preparations. In short, those steps are: fixation, embedding, slicing and staining.

On the other hand, the film had to put the spotlights on the specific knowledge gained through years of meticulous practice of the lab technician. These techniques involve a lot of understanding and skills. The makers of slides learn this technique by doing it, by experimenting and constantly improving themselves. The learning process and the muscle memory they build are very important and defining concepts of intangible heritage. A lot of attention and concentration is needed for cutting. The lab technician has to ‘feel’ how thick the section can be without the material tearing apart. She has to check whether all particles of the tissue are well embedded and whether there are no holes in the section. She has to make sure that the pressure exerted on the knife is the same everywhere. Those things are part of the internalised feeling of the technique and the senses of the technician: it’s about hearing a ‘clic’, have the right feeling with the embedded tissue and knowing by touching and seeing it if it will be a good slide. Regular practice is the key to success, as with any craft!

Makers of slides mostly work in scientific and medical environments, such as histology labs, universities, hospitals, faculties of biology, biomedical sciences or veterinary medicine. They pass on their knowledge while doing and showing it, to students and starting colleagues. It is a process of trial and error. International conferences on this technique are a great success, for example in the United States of America. The participants are all practitioners and learn tips, tricks and novelties by building up the network with other histology lab technicians.

Preparaten_The microtome is ready for slicing (c) ETWIE


The result is a 5-minute film about the making of microscopic preparations at the laboratory of histology at the University of Ghent. You can see it here!

This is just one example of intangible heritage at the university. There are many more! It’s important to keep those techniques and knowledge alive, and to safeguard them to the future. After all, it’s part of our cultural identity, and in case of universities, technical knowledge and intangible heritage often leads to more research, innovation and experiment.

Special thanks to:

  • Barbara De Kegel, Department of Biology

  • Muriel Grégoire

  • University of Ghent and GUM - Ghent University Museum

  • Viktoria Verhelst