Head of an ox

This head of an ox, carved in marble and resting on a wooden tree trunk, contains an unusual curiosity. In the centre of the ox's head is a cavity in which rests a 'stone' identified as an osteoma, a new piece of bone growing on another (typically a skull) which was originally thought to be the fossilised or petrified brain of an ox. This may have been based on an event in Padua in 1670, when a hardened mass of bone was discovered inside a slaughtered ox.

The discovery created a sensation, as it was believed that the brain of the animal had become petrified during its lifetime. In 1933, the Natural History Museum confirmed that the huge osteoma displayed here was organic and likely to be a piece of diseased bone from a large mammal, such as an elephant or whale.