It is extremely rare for a medical doctor to eventually become a Professor of physics. Further, he not only invented opthalmoscope – an instrument we use to look inside an eye, but also unravelled mysteries of sound, principles of mathematics, as well as that of human thought. This person is Hermann Helmholtz, who initially trained as a physician, and later established German physical research society.
Medicine and Physics
Hermann Ludwig Ferdinand Helmholtz was born in Potsdam, Germany (then Prussia) in 1821. In 1838, he started his training as a medical student at Friedrich Wilhelm Institute of Medicine and Surgery, to fulfill his father’s desire that he should become a doctor. Since his parents were not very well off, study of medicine was also covered by a scholarship, while other fields were not. His thesis was on structure of the nervous system, and he postulated existence of nerve cells that transmit signals. This idea was a first of its kind, in those times.
As he was writing his final examination towards completion of his medical qualifications, he started attending sessions by a physicist Gustav Magnus. Gustav also had a physics ‘ laboratory, where many of his students could perform experiments. Later in his career, Helmholtz became Magnus’ successor, and moved the laboratory to the building of Berlin University. This was to become Berlin Physical Society and later German Physical Society.
Early in his scientific work, Helmholtz applied principles of physics to human functioning. Helmholtz strongly argued for founding physiology completely on the principles of physics and chemistry. In 1845, he published an article about the consumption of matter during the work of muscles. He gave principle of the conservation of energy. Energy is not infinite, but is merely converted from one form to another. His work on muscle metabolism brought him as a faculty of physiology and pathology at Königsberg University in Eastern Prussia. Later, in 1858, Helmholtz became a professor of physiology in Heidelberg.
Invention of Opthalmoscope
Around 1850, Helmholtz became interested in physiology of vision. He received great acclaim for his invention of the ophthalmoscope in 1851 and rapidly gained a strong international reputation. In 1852 he published important work on physiological optics with his theory of color vision. His later expanded second volume on Handbook of Physiological Optics, in 1856 is considered as a landmark. Thereafter he also went on to invented devices to measure corneal curvature, and to look at the back and front crystalline lens surface. Helmholtz not only invented opthalmoscope, but also described retina. Retina has three types of sensitive fibres for red, blue and green beams, and his color theory postulated that all variety of colors are seen with these three cell types.
Nerves and Sound
He designed experiments and measured speed of nerve conduction, and later started working on physiological acoustics. In 1863, he wrote a book on sensation of tone, and how we perceive music. His classical works on hydrodynamics and the basics of geometry also appeared at this time. From around 1866 Helmholtz began to move away from physiology and move more towards physics.
Legacy of Physics
In 1871, Helmholtz became a professor of Physics at the Berlin University. He set up the Physical Institute, and also established a centre of German metrology. A major topic which occupied Helmholtz after his appointment to Berlin was electrodynamics. He also attempted to give a mechanical foundation to thermodynamics. Thousands of students attended his lectures, and best scientists of the day such as Heinrich Hertz, Max Planck, Heinrich Kayser, Eugen Goldstein, Wilhelm Wien were his students.
Later work of Maxwell, Hetrz, Faraday, and later Einsteinn disproved many of his electrodynamic theories. When Hermann Helmholtz died on the 8th of September, 1894, many principles of physics such as X-rays, radiation, and relativity were yet to be discovered. However, his foundations are considered vital for these later discoveries.
