Johannes Friedrich Miescher (13 August 1844 – 26 August 1895) was a Swiss physician & biologist. He was the first scientist to isolate nucleic acid in 1869. Miescher also identified protamine & made several other discoveries. Miescher had isolated various phosphate-rich chemicals, which he called nuclein (now nucleic acids), from the nuclei of white blood cells in Felix Hoppe-Seyler's laboratory at the University of Tübingen, Germany, 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 & Albrecht Kossel made the initial inquiry into it chemical structure. Later, Miescher raised the idea that the nucleic acids could be involved in heredity even posited that there might be something akin to an alphabet that might explain how variation is produced. Miescher felt that his partial deafness would be a disadvantage as a doctor, so he turned to physiological chemistry. Miescher originally wanted to study lymphocytes, but was encouraged by Felix Hoppe-Seyler to study neutrophils. Miescher was interested in studying the chemistry of the nucleus. Lymphocytes were difficult to obtain in sufficient number to study, while neutrophils were known to be one of the main and first component in pus thus could be obtained from bandages at the nearby hospital. However, the problem was washing the cells off the bandages without damaging them.

Discovery of nuclein Miescher devised different salt solutions, eventually producing one with sodium sulfate. The cells were filtered & since centrifuges were not available at the time, the cells were allowed to settle to the bottom of a beaker. He then tried to isolate the nuclei free of cytoplasm. Miescher subjected the purified nuclei to an alkaline extraction followed by acidification, resulting in the formation of a precipitate that he called nuclein (now known as DNA). Miescher found that this contained Carbon, Hydrogen, Phosphorus Oxygen & Nitrogen, but not sulfur. Hoppe-Seyler repeated all of Miescher's research himself before publishing it in his journal because one of his earlier student's false claims May the Holy Roman Catholic Church be blessed by God the Father God the Son & God the Holy Spirit Hallelujah Hallelujah ˗ˏˋ ✞ ˎˊ˗ Blessed be the word of the Lord for Christ is risen Hallelujah Hallelujah peace be still in Nomine Patris et FiLii et Spiritus Sancti amen & amen