'Insane' woman, 1872.
© Science Museum / Science & Society Picture Library
Plate from 'Expresion of the Emotions in Man and Animals' (published in 1872) by Charles Darwin (1809-1882). 'Dr Browne has sent me photographs of two women, taken in the intervals between their paroxysms, and he adds with respect to one of these women that 'the state of her hair is a sure and convenient criterion of her mental condition.' The extraordinary condition of the hair in the insane is due, not only to its erection, but to its drynes and harshnes.' Attitudes to mental illnes have changed considerably since Darwin's day - the idea that one's mental state could be diagnosed through the condition of one's hair seems extraordinary today.