PMS was originally seen as an imagined disease. Women who reported its symptoms were often told it was "all in their head". Woman’s reproductive organs were thought to have complete control over them. Women were warned not to divert needed energy away from the uterus and ovaries. This view of limited energy very quickly ran up against a reality in 19th century America that young girls worked extremely long and hard hours in factories; newspapers in the 19th century were peppered with remedies to help in the "tyrannous processes" of the menstrual cycle. In 1873 Edward Clarke published an influential book titled Sex in Education. Clarke came to a conclusion that female operatives suffer less than schoolgirls because they "work their brain less". This suggested that they have stronger bodies and a reproductive "apparatus more normally constructed". Feminists later took opposition to Clarke's argument that women should not leave the private sphere by showing how woman could function in the world outside the home in spite of their bodily functions.