The disease of the hypochondriac consists in this: that certain bodily sensations do not so much indicate a really existing disease in the body as rather merely excite apprehensions of its existence: and human nature is so constituted – a trait which the animal lacks – that it is able to strengthen or make permanent local impressions simply by paying attention to them, whereas an abstraction – whether produced on purpose or by other diverting occupations – lessen these impressions, or even effaces them altogether.