Rudolf Albert von Kölliker

The contribution of Rudolf Albert von Kölliker (1817-1905), professor of physiology and comparative anatomy at the University of Würzburg, to our understanding of the nervous system lies in his observations on histology, or cellular structure, and lead directly to the findings of Cajal and Sherrington Scott.

Nerve axons and their neurolemma as depicted in Rudolf Albert von Kölliker's Manual of human histology. Volume 1. London: printed for the Sydenham Society, 1853 [KCSMD Historical Collection QM551 KOL]Kölliker and other scientists were better able to undertake histological research than before because the microscope in Germany had been improved during the 1820s to such an extent that the obstacles which seventeenth century microscopists had encountered in their investigations had been overcome. The amateur scientist Anton van Leeuwenhoek had observed nerve cells, but the microscopes which he used produced distorted images. The cells which he wanted to study did not stand out from the surrounding fluids or the background.

Another complicating factor is that neurons do not look like other human or animal cells under any kind of microscope, so it must have been difficult to discern that the brain has a cellular structure. In the new microscopes, the use of doublet lenses of lead and flint glass enabled scientists to focus on different colours at once. Moreover, in the nineteenth century more satisfactory procedures for preparing specimens for dissection were adopted, using alcohol or chromic acid (previously, it had been common for specimens not to be ‘hardened’ for dissection).

Through microscopy, Robert Remak discovered that nerve axons were continuous with nerve cells in the spinal cord and observed the neurolemma (myelin sheath of nerve fibres). Johannes Purkinije showed that nerve cells had a protoplasm-filled main body (the nucleus) and a fibrous ‘tail’ (the process) extending from the main body. Kölliker showed that the nerve fibres (as seen here) were secondary to nerve cells and that some of them were the processes of nerve cells. Augustus Volney Waller confirmed this by showing that if a bundle of nerve fibres were cut, the parts separated from their cells rapidly degenerated. However, the nerve cell’s role in electrical action and the question of whether or how the nerve cells were connected still had to be elucidated.

This copy of Kölliker’s Manual contains the bookplate of Robert Bentley Todd.

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