He was a Danish physician, the father of the physicist and Nobel laureate Niels Bohr, as well as the mathematician Harald Bohr and grandfather of another physicist and nobel laureate Aage Bohr. He wrote his first scientific paper, ("On salicylic acid's influence on the digestion of meat"), at the age of 22. He received his medical degree in 1880, studied under Carl Ludwig at University of Leipzig, took a Ph.D. in physiology and was appointed professor of physiology at the University of Copenhagen in 1886. In 1891, he was the first to characterize dead space. In 1903, he described the phenomenon, now called the Bohr effect, whereby hydrogen ions and carbon dioxide heterotopically decrease hemoglobin's oxygen-binding affinity. This regulation increases the efficiency of oxygen release by hemoglobin in tissues, like active muscle tissue, where rapid metabolization has produced relatively high concentrations of hydrogen ions and carbon dioxide.