Florence Nightingale nearly died from an illness during the Crimean War, probably caught from drinking untreated milk. This disease, brucellosis, can produce recurring fevers for years afterwards. But some writers have claimed that brucellosis made her neurotic. There is no medical justification for their claim, which has been used to discredit her achievements in later life.
Read about her illness and the multiple efforts over the years to use it against her, in Florence Nightingale’s Pandemic. The book reveals just how inconvenient she was to those with property and power, how she changed the law to save millions of people from fatal epidemic disease, and how we have misrepresennted her as ‘just a nurse’.
Meanwhile, here’s a scientific account of her probable case of brucellosis:
Link to Dr. D A B Young’s paper on Florence Nightingale’s Fever