But with the help of a guide like Dr Crump, subtlechanges in the balance of nature can be observed: with the limpet population practically wiped out by the oil, the particular seaweed they used to feed on was allowed to thrive, changing the look of the rocks.
Though these changes can go unnoticed by a person with a disease, relatives and friends more often pick up on it, but a computer algorithm that detects nuances of speech and subtlechanges could detect abberations with much greater frequency.