Neuropathologists dissect brains after death to confirm diagnoses and to learn what diseases do to tissue. The brain is cut in half and sliced into thin cross-sections, which show grey cortex on the outside and white matter of myelin-wrapped fibres beneath it. Shrinkage of the brain and enlarged ventricles can signal Alzheimer's, while microscopic plaques and tangles confirm the disease. Parkinson's shows up as loss of dopamine-producing cells in the substantia nigra, along with Lewy bodies in the brainstem. Such donated tissue is essential because living brains cannot be examined in this way. Deep brain stimulation, which has been used on around 200,000 patients, can ease the symptoms of Parkinson's even though there is no cure.

In 1909 D. W. Griffith made a 14-minute film about a speculator who corners the wheat market and doubles the price of bread. A farmer sows his field while a 'Wheat King' gambles in the Chicago wheat pit; bakers raise the loaf from five cents to ten and the poor line up for bread. Griffith cut back and forth between the farm, the feast and the breadline, a technique called parallel editing, so audiences saw both ends of the economy at once. The film drew on Frank Norris's stories and on a real scheme: months earlier Chicago financier James Patten had cornered wheat, sent bread prices up and made about $5 million, roughly $185 million today.