Neurologists of the early 19th century relied on gross anatomy. The development of the compound microscope, techniques for tissue fixation and embedding, and the use of a microtome were essential inventions for the microscopic study of the nervous and other systems. Histology applying these methods to neural tissue was in large part the achievment of Robert Remak1 and his former student Rudolph Albert von Kölliker (1817–1905). Until the 1830s, the microscopic anatomy of the neuron, axon, and their connecting processes were not understood. Remak (1838) had noted “primitive bands” that probably were nerve sheaths, but it was Theodor Schwann (1810–82) who first described in 1838 the myelin sheath as a fatty deposit on the inner surface of the structureless cell membrane (called the neurilemma by Bichat). By the use of a compound microscope, Remak was able to prepare a histological monograph2 on the nervous system. Kölliker's text3 included accounts of various forms of nerve cells as well as:

“a good many fine, pale fibres, like the processes of cells,...whether they are nerve tubes or are to be referred …