<P> Some time later Munting meets Lathom by chance in London and learns that he is holidaying with Harrison at the latter's isolated cottage in Devon . Harrison's hobby is foraging for wild food, and he is an expert on edible mushrooms . Lathom persuades Munting to accompany him back to Devon, where they find Harrison dead, apparently having cooked and eaten poisonous fungi by mistake . However Harrison's son Paul suspects that Lathom and his stepmother have conspired to murder Harrison, and Munting is drawn unwillingly into the investigation . He discovers accidentally that muscarine - the poison that killed Harrison - can exist in a natural or a synthetic form . The molecules of both forms are asymmetrical; however the natural form is optically active - consisting of only one molecular form; the synthetic form is racemic - with equal quantities of both types of molecule; and the two forms can be distinguished only by using polarised light . The muscarine consumed by Harrison proves to be synthetic, indicating that the mushrooms he ate were poisoned deliberately . Letters between Mrs Harrison and Lathom indicate that she manipulated him into the killing by claiming that she was expecting his child . Lathom is hanged for murder . </P> <Ul> <Li> John Munting--an aspiring young writer </Li> <Li> Harwood Lathom--a struggling artist, acquaintance of Munting </Li> <Li> George Harrison--middle - aged downstairs neighbour of Lathom and Munting </Li> <Li> Margaret Harrison--considerably younger than her husband . Engaged in a secret affair with Lathom </Li> <Li> Agatha Milsom--live - in spinster companion of Mrs Harrison </Li> <Li> Paul Harrison--engineer; adult son of Mr Harrison by a previous marriage . </Li> </Ul> <Li> John Munting--an aspiring young writer </Li> <Li> Harwood Lathom--a struggling artist, acquaintance of Munting </Li>

Who wrote the first major publication to document poisonings