HIS, WILHELM

born Dec. 29, 1863, Basel, Switz. died Nov. 10, 1934, Wiesental Swiss cardiologist (son of the renowned anatomist of the same name), who discovered (1893) the specialized muscle fibres (known as the bundle of His) running along the muscular partition between the left and right chambers of the heart. He found that these fibres help communicate a single rhythm of contraction to all parts of the heart. A professor of medicine at the University of Berlin (190726), His was one of the first to recognize that the heartbeat has its origin in the individual cells of heart muscle. born July 9, 1831, Basel, Switz. died May 1, 1904, Leipzig, Ger. Swiss-born German anatomist, embryologist who created the science of histogenesis, or the study of the embryonic origins of different types of animal tissue. His discovery (1886) that each nerve fibre stems from a single nerve cell was essential to the development of the neuron theory, which states that the neuron, or nerve cell, is the basic unit of the nervous system. A student of Johannes Mller at the University of Berlin and of Rudolf Virchow at the University of Wrzburg, His taught at the universities of Basel (185772) and Leipzig (18721904), where he founded an institute of anatomy. In 1865 His invented the microtome, a mechanical device used to slice thin tissue sections for microscopic examination. He was the author of Anatomie menschlicher Embryonen, 3 vol. (188085; Human Embryonic Anatomy), considered the first accurate and exhaustive study of the development of the human embryo.