I felt I had to answer the incorrect facts given by Graham Chainey in his letter about Florence Nightingale having ME.

I am an ME sufferer and did not contract it from chemicals but from a virus - most ME sufferers do.

Chemical and food intolerance are all part of this illness, as the liver and lymphatic system becomes overloaded, but this is not the main cause.

Charles Darwin's condition began (in his own words) from a tropical virus he contracted in South America - not the preserving of specimens, as Graham states.

I also question his ideas about ME being a modern illness - as if "chemicals" and living in poisonous environments were a modern phenomenon.

People have been living and working with chemicals for hundreds of years - look at the Victorians.

I simply believe, because there was no diagnosis, their illness went unrecorded.

There are cases in history that are quite obviously ME but are not described in terms we are familiar with - a woman in 18th-Century Wales was bedridden with food intolerance, which started at age 13, after a fever.

I take great exception to Graham Chainey's unpleasant terminology in saying "sufferers identify with historical invalids".

I do not need to identify with anyone on paper but, like other sufferers, want the illness to be better profiled and understood - so no more petty spite please.

-Christine Jones, Peacehaven