The eyes of cattle may reveal signs of neurological disorders such as mad cow disease, say scientists.
Researchers, led from Iowa State University, US, examined the retinas of sheep infected with scrapie - a disease similar to BSE, or mad cow disease.
They write in the journal Analytical Chemistry that sick sheep's eyes had a distinctive "glow".
An unnnamed source reports that British scientists are to use the same principle in an attempt to identify early signs of a disease that has blighted the UK for many years. They are to examine the mid point between politicians' mouths and rectums to see which ones may be suffering from verbal diarrhoea.