Writer: Amy Joseph
Editor: Ayotenu Dosumu
Jeremy Bentham is a name familiar to most philosophy enthusiasts; to many UCL students, he is a more literal presence. Bentham’s 194-year-old ‘Auto-Icon’ (a self-coined term to describe his preserved body) sits in the Student Centre, watching over the university shaped by his utilitarian ideals. While it is widely known that Bentham’s preserved head was once stolen by KCL students (for a fine ransom of £10), far fewer are aware that Bentham requested his head be preserved using the Mokomokai method of the Māori people—and that his friend (who also served as his embalmer) attempted to carry this out with disastrous results.
Central to Mokomokai preservation was Ta moko, intricate tattoos carved into the face with bird bones. When a person with facial moko passed away—often a great leader or a cherished individual—their head would be preserved in a process developed over generations. It was only in the 19th century that this tradition declined, as British colonialism and the commodification of Mokomokai as ‘curios’ fuelled their trade with Māori communities in exchange for weapons; once the Musket Wars subsided, this ancient practice diminished.
Mokomokai preservation was relatively simple but scientifically grounded. Firstly, biological control was established: all soft tissues, most notably the brain, were removed to prevent putrefaction. The head cavities and nasal orifices were then filled with clay and vegetal fibres, respectively. These steps reduced moisture, limiting bacterial metabolism and consequent gas build-up.
Mechanical interventions followed to preserve facial topology. Using vegetal fibres, the eyelids and nostrils were sewn shut, which also prevented the entry of microbes and insects; the cervical skin was fixed to the skull base. A wooden pin was inserted under the nose to prevent lateral deviation of the skin when dried in subsequent steps. These measures ensured even shrinking; both the detailed Ta moko and the facial features of the deceased remained recognisable.
Thermal fixation was the next ingenuity: the head was steamed or boiled, then smoked, and finally sun-dried. The use of wet heat ensured controlled and sustained temperatures that destroyed both decomposing microorganisms and tissue-digesting hydrolytic enzymes from the body’s own cells. Furthermore, when exposed to high enough temperatures, proteins first denature (uncoil their chains) and then permanently coagulate (clump together) — think of the way an egg white firms up as it cooks. Once coagulation occurs, proteins in the skin form a dense, three-dimensional network that resists the mobility of small molecules, such as water, perhaps contributing to the long-term stabilisation of the tissue. Phenols and acids present in smoke contribute to its antimicrobial properties, further preventing decay; sun-drying as the penultimate step ensured slow, even dehydration of the skin.
The finishing touch—the application of shark oil on the Mokomokai—both moisturised the skin and reduced its consumption by insects. Shark oil is hydrophobic: insects repelled by its stench would struggle to lay eggs on its slippery surface. These factors, coupled with the possibility of the oil clogging the spiracles of the hungry invertebrate, would make the embalmed head a very unprofitable meal.
In contrast, Bentham’s head was crudely preserved. After removing the brain, his friend Dr Thomas Smith placed the head in a sealed chamber with concentrated sulphuric acid, using an air pump to circulate acidic vapours. Moisture that evaporated from the head was trapped by the acid, which is strongly hygroscopic (extremely absorbent of water). While this technically fulfilled the dehydration requirements of the embalming process, due to the lack of mechanical support, Bentham’s face became shrunken and unrecognisable. Furthermore, disregard for thermal fixation caused chaotic denaturation of proteins and uncontrolled lipid oxidation. Therefore, Bentham’s head discoloured, and his skin became brittle and vulnerable to microbial degradation.
Today, Mokomokai heads are globally dispersed in museums (such as the British Museum) due to their theft and trade. Remarkably, Te Papa Tongarewa’s ongoing repatriation efforts have led to the return of several Mokomokai heads. Bentham’s head, however, is kept in a secret location in UCL, presumably to hinder further thefts by unscrupulous students or prevent nightmares among those unfortunate enough to glimpse his macabre expression.
kinesismagazine.com 