Into the making of a wax anatomical model

Un film de Siddhant Modi
Master I, Didactique visuelle – Haute école des arts du Rhin
Institut National du Design – Ahmedabad, Inde
Traduction et voix par Ana-Maria Pojoga
Master I, Didactique visuelle – Haute école des arts du Rhin

During the eighteenth century, in Florence, anatomists and artists such as Felice Fontana or Clemente Susini worked on the creation of anatomical wax models in the workshops of the Natural History Museum of La Specola.

These models are a three-dimensional vision of the most recent anatomical discoveries, found in contemporary books and writings. Their advantage and innovation consists of presenting the human body with realism and context.

The manufacturing process of a wax model involves multiple steps. Firstly, a prosector is needed to dissect corpses. The corpses are placed in a similar way as they would appear in the scientific illustrations. In order to achieve accurate observations, as well as to overcome the fast degradation of the dead body, the prosector can dissect up to a hundred corpses while working a unique model. During this long and precise process, new discoveries can be made.

The second step is to take the imprint for the mold directly on the organ. In case the organ is too complex to make a direct imprint, or if the model is not the same scale as the original organ, a sculptor shapes a replica in clay, rough wax or chalk.

Then, the moulder ties a cord around the object and then covers it with plaster. The cord is removed while the plaster is still soft, in order to make it possible to detach the two halves of the mould. Once the plaster is dry, the mould is detached and cleaned.

White wax from Smyrna, Chinese or Venetian wax are commonly used for the final prototype. To ensure its quality and avoid discoloration, the wax is slowly melted in a water bath. Improvements might be necessary and involve adding turpentine or resins to improve the elasticity of the wax, or again pigments to improve the color.

Before pouring the wax, the mold should be dampened with lukewarm water and rubbed with soft soap, to ensure an easier removal of the mould. If the wax piece is not tainted in the mass, then the mould itself is painted, layer by layer. The color then appears when the model is removed from the mold.

The two halves are empty in the middle and can be filled with cloth, wood or hemp chips. Sometimes the model is reinforced with a metal armature. The edges of the casting mold are heated to merge the two halves. After the unmolding, the rough surface of the joint is concealed with warm wax.

The wax organs are then assembled into the desired composition. Blood vessels and nerves are made out of cotton thread and soaked in wax. To add realistic details, they can also be painted directly on the prototype afterwards. On the face and the scalp of the model, real animal and, or, human hair is implanted one by one.

Once the model is ready, it is covered with a turpentine based varnish. That will protect it from dust, give it a natural luster and make it look more like a freshly dissected corpse.

Finally, the model is placed in a sophisticated glass showcase, lined with silk fabric. Under each showcase a small drawer containing complementary information and an illustration of the model can be found.

After months of hard work the model is finally exhibited at the Museum of La Specola. Anatomists and craftsmen have collaborated shoulder to shoulder to accomplish the task. Medical students, intellectuals, amateurs or curious Florentine visitors are enthusiastic to discover this amazing revelation of the human anatomy.