Op woensdag 13 mei 2015 is op 82-jarige leeftijd prof.dr. R.A. de Melker overleden. Hij was van 1984 tot 1997 hoofd van de afdeling Huisartsgeneeskunde in Utrecht. Ruut de Melker was een van de grondleggers van de moderne academische huisartsgeneeskunde in Nederland. Voortbordurend op het werk van Frans Huygen, zijn leermeester in Nijmegen, heeft hij, als opvolger van Jan van Es, in Utrecht het fundament gelegd voor de academische huisartsgeneeskunde zoals die nu bestaat. Gedurende zijn hele carrière had hij bovenal oog voor de klinische kant van de huisartsgeneeskunde: in de dagelijkse praktijk, in zijn onderzoek en het onderwijs.

Franciscus Cornelis Donders was educated at Duizel and Boxmeer before entering the Military Medical School and the medical faculty at Utrecht University in 1835. In 1840, he received his MD from Leiden and spent 2 years in practice at Vlissingen before returning to Utrecht, where he was appointed as an extraordinary professor to lecture on forensic medicine, anthropology, general biology and ophthalmology. Refraction by the eye is complex, since the ray of light passes through many changes of refractive index in its path, and Donders simplified the account of the process by establishing an equivalent refractive system: the reduced eye. When Donders opened an Eye Hospital in 1858, he devoted himself to clinical ophthalmology, making fundamental advances in providing spectacles to correct errors of refraction-which he separated from errors of accommodation. In 1862, Donders was promoted as an ordinary professor at Utrecht and he handed over the greater part of his practice to his pupil Hermann Snellen. From narrow specialisation, Donders was freed to return to the broader physiology; subatmospheric pressure in the pleura was for a while referred to as 'Donders' pressure'; he also devised a method of measuring the mental reaction time taken in making discrimination, rather than the simple reaction time in which no choice is involved. He was widely honoured, presiding at international congresses, and elected as a foreign member of the Royal Society. He died suddenly on 14 March 1889, but his work lives on.

Einthoven not only designed a high quality instrument, the string galvanometer, for recording the ECG, he also shaped the conceptual framework to understand it. He reduced the body to an equilateral triangle and the cardiac electric activity to a dipole, represented by an arrow (i.e. a vector) in the triangle's center. Up to the present day the interpretation of the ECG is based on the model of a dipole vector being projected on the various leads. The model is practical but intuitive, not physically founded. Burger analysed the relation between heart vector and leads according to the principles of physics. It then follows that an ECG lead must be treated as a vector (lead vector) and that the lead voltage is not simply proportional to the projection of the vector on the lead, but must be multiplied by the value (length) of the lead vector, the lead strength. Anatomical lead axis and electrical lead axis are different entities and the anatomical body space must be distinguished from electrical space. Appreciation of these underlying physical principles should contribute to a better understanding of the ECG. The development of these principles by Burger is described, together with some personal notes and a sketch of the personality of this pioneer of medical physics.