Editing Development of Darwin's theory (section)

===Annie falls ill===
Darwin returned from Malvern at the end of June 1850 to a reawakening of his fears that his illness might be hereditary. His bright nine-year-old daughter Anne who had become a particular favourite and comfort to him fell sick. She was miserable for weeks on end, then became feverish. Their doctor could do nothing and thought it might be inherited. She had recovered to some extent by March 1851, but then she and her father were both laid low by [[influenza]]. Darwin recovered but Annie was still ill, and on 24 March he took her to Malvern, leaving her there for the best treatment he knew of, and returning to Downe where Emma had stayed as she was pregnant. With his first paper on barnacles printed and Hooker safely returned to Britain laden with specimens, things were looking up, but then on 15 April Annie suffered a serious relapse and Darwin had to rush to her side.

An agonised Darwin stayed at Annie's bedside as the crisis deepened. Dr Gully attended through the night thinking her unlikely to last, but at 6 a.m. she vomited and her condition stabilised. She seemed to recover slightly and a series of ups and downs followed with Darwin and [[Fanny Wedgwood]] anxiously watching and writing home, but she deteriorated and died on 23 April 1851.

Darwin's faith in Christianity had already dwindled away and from around 1849 he had stopped going to church.<ref name=jvw41>{{harvnb|van Wyhe|2008|p=41}}</ref> During Annie's long illness Darwin had read books by [[Francis William Newman]], a Unitarian evolutionist who called for a new post-Christian synthesis and wrote that "the fretfulness of a child is an infinite evil". For three years Darwin had deliberated about the Christian meaning of mortality, opening a vision of tragically circumstantial nature. On 30 April he wrote a brief and intensely emotional memoir of Annie for himself and Emma.