Johannes Friedrich Miescher (August 13, 1844 - August 26, 1895) was a Swiss physician and biologist. Miescher isolated various phosphate-rich chemicals, which he called nuclein (now nucleic acids), from the nuclei of white blood cells in 1869, paving the way for the identification of DNA as the carrier of inheritance. The significance of the discovery, first published in 1871, was not at first apparent, and it was Albrecht Kossel who made the initial inquiries into its chemical structure. Later, Friedrich Miescher raised the idea that the nucleic acids could be involved in heredity. He is also known for demonstrating that carbon dioxide concentrations in blood regulate breathing. He died of tuberculosis in 1895 at the age of 51. No photographer credited, undated.