Today is the birthday of Willam Prout, born in 1785, he was a practicing physician who became interested in organic chemistry. He identified HCl as the acid in stomach secretions in 1824. In 1827 he divided the foodstuffs into groups that today we call carbohydrates, proteins and fats. In 1815 he said that the atomic weights were integral multiples of hydrogen. This was called the Prout Hypothesis.