Hurley's remarkable visual record forms the core of both Ms Alexander's book and the exhibition.

ECONOMIST: Antarctic exploration

Endless Forms: Charles Darwin, Natural Science and the Visual Arts will be open at the Fitzwilliam Museum, in Cambridge, until 4 October 2009.

BBC: Friday 11 September: Darwin special

Cell-phone conversations and other forms of multitasking may slow down the mental and visual processing required to gauge the distance and speed of oncoming cars, the study suggests.

CNN: Multitasking and crosswalks a risky mix for elderly

Tension headaches can sometimes be difficult to distinguish from migraines, but unlike some forms of migraine, tension headache usually isn't associated with visual disturbances (blind spots or flashing lights), nausea, vomiting, abdominal pain, weakness or numbness on one side of the body, or slurred speech.

CNN: Tension headache