Ewald Weibel, former director of the Institute of Anatomy at the University of Bern, Switzerland, died in Bern on 19 February 2019 after a short illness. He was a leader in microscopical anatomy, a superlative teacher, an academic mentor to many, a prolific researcher and collaborator, and a pioneer of biological applications of stereology, notably (but not exclusively) to sections of lung. In truth, in most of these areas of endeavour, he was a giant.
He was born in Buchs within the northern Swiss canton of Aargau. His father was a typewriter mechanic and his mother a seamstress. He first showed interest in investigative science whilst attending the cantonal school in Aarau. This is the same school that Albert Einstein had attended many years earlier, and at which Einstein pondered the question ‘What would a light wave be like if I travelled with it at the same speed?’ After qualifying at the Medical School in Zurich, Ewald married his lifelong partner, Verena, and took up a teaching fellowship in the Institute of Anatomy. In 1958, he obtained a research fellowship to undertake studies on bronchial arteries at Yale University.
A year after arriving in the USA, fortuitously, he was recruited by André Cournand and Dickinson Richards at Columbia University to do ‘any sort of research on the structure of the lung that would be of physiological interest’. There, he met Domingo Gomez who was trying to create a theoretical model of pulmonary gas exchange, and for which he wanted to know structural quantities such as the number of alveoli and total alveolar surface area. Their collaboration led not only to a method for counting alveoli but, more importantly, to a lifelong interest in stereology, the acquisition of 3D structural quantities from measurements made on 2D microscopical sections.
By 1961 (the year in which the term stereology was coined), he reached something of an impasse in his studies of the lung using light microscopy, and persuaded Cournand to send him to George Palade at Rockefeller Institute in order to receive training in electron microscopy. On St Valentine's Day in 1962 (coincidentally, his father's 60th birthday), whilst observing electron microscopy sections of rat lungs, he noticed that the endothelium of a small artery contained some membrane‐bound, rod‐shaped structures. After showing them to Palade, a search through collections of micrographs of vessels from different sites and different species revealed that these rod‐shaped organelles were present in the endothelium of every artery! Today, following a seminal paper (J Cell Biol, 23, 1964), they are known as Weibel‐Palade bodies. They contain von Willebrand Factor, which is released from injured endothelium in order to assist in blood clotting.
In 1963, he published his influential book ‘Morphometry of the Human Lung’ (1963, Springer) based on his experiences of undertaking research into quantitative structure–function in that organ. Later, he was to publish a pioneering review article ‘Stereological principles for morphometry in electron microscopic cytology’ (Int Rev Cytol, 26, 1969). Also in 1963, he became the secretary for the first board of the fledgling International Society for Stereology, and took over the presidency of the second board from Hans Elias in 1967.
On leaving the USA in 1963, Ewald returned to Switzerland and took up the post of Assistant Professor at the University of Zurich where he set up the first electron microscopy laboratory. A few years later, he moved to the University of Bern as Professor and Chairman of the Institute of Anatomy. His research funding supported the work he was undertaking into quantitative microscopical anatomy of the lung and other organs, tissues and cells. There followed a golden period of publication and collaboration with colleagues like Peter Burri, Luis Cruz‐Orive, Hans Hoppeler, Willy Stäubli and many others.
My first encounter with Ewald occurred sometime in early 1970. At a critical phase in my PhD studies at the University of Sheffield, my supervisor, Mike Williams, suggested that I travel down to London to listen to a talk on the quantitation of lung microstructure given by Ewald Weibel. I was mesmerised by the speaker, the topic and the technique. On my return to Sheffield, I changed course in my research and decided to apply stereological tools in order to quantify aspects of macrophage stimulation at the ultrastructural level. It was to change my academic life completely.
In 1974, Ewald was awarded the Marcel Benoist Foundation Prize, given to scientists of Swiss nationality or residency who made useful discoveries pertinent to human life. In fact, it was given in recognition of his ground‐breaking work on the functional morphology of the lungs and for his work on perfecting morphometry and stereological methods to analyse electron micrographs of cells and tissues. In 1979, the first of two volumes on stereological methods, ‘Vol 1, Practical Methods for Biological Morphometry’ (Academic Press) appeared. In autumn of that year, he was invited by Harvard University to deliver a series of Agassiz Lectures on ‘Structure and Function in the Respiratory System’. Later, the lectures were transformed into a remarkable book entitled ‘The Pathway for Oxygen’ (1984, Harvard University Press), which incorporated some of the results of fruitful collaborations with C Richard Taylor from the Museum of Comparative Zoology at Harvard (see also ‘Design of the mammalian respiratory system’, Respiration Physiol, 44, 1981). These studies could rightly be regarded as a pioneering attempt at what is now termed Systems Biology.
In 1981, Ewald became a foreign member of the United States National Academy of Sciences and, in 2000, a foreign honorary member of the American Academy of Arts and Sciences. He was also a Fellow of the Royal Microscopical Society.
His innovative work on estimating the morphometric diffusive conductance of the lung was the inspiration behind my attempt (1984–1988) to do the same for the human placenta in collaboration with Jere Haas at the University of Ithaca. In turn, this stimulated my interest in the functional morphology of the placenta in normal and various compromised pregnancies.
Following his retirement, Ewald became Professor Emeritus at the University of Bern but, to the end, he remained active and influential in research collaboration, refereeing, mentoring of junior researchers, scientific writing and much more. Indeed, many of us who attended his 80th birthday celebrations in Bern in 2009 shared the strong feeling of his being a father figure from whom we had received ‘science batons’ and carried them onwards to pass on to the next generation. If he handed on the ‘stereology baton’ to Luis Cruz‐Orive, Hans Gundersen, Vyvyan Howard and myself, we, in our turn, passed it on to others including Peter Dockery, John Lucocq, Christian Mühlfeld, Jens Nyengaard, Matthias Ochs, Matt Reed and others too numerous to mention. Indeed, this very year, Ewald will publish an article ‘On the topological complexity of human alveolar epithelial type 1 cells’ co‐written with Mühlfeld and Ochs. This employs one of the latest volume imaging techniques, serial block‐face scanning electron microscopy (Am J Respir Crit Care Med, 2019).
Apart from his books, he published over 250 research articles and reviews, and refereed or served on the editorial boards for multiple peer‐reviewed journals. This rich experience cultivated a determined but constructive critique that benefitted many a submitted manuscript, including some of my own!
Ewald and Verena had no children, but they enjoyed life together in a beautiful house in Bern overlooking the Swiss Alps and where he cultivated a small vineyard. Verena's long‐term health problems meant that he could not travel as often as he wished as he wanted to care for her at home. Sadly, Verena is now in need of attention in a residential care home.
It was a great honour to know this man. To celebrate the life of one so dedicated to undertaking and promoting investigative science, it is fitting to end with a quote from that other scientific giant who also spent time at the college in Aarau and worked for a while in Bern:
‘The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science. He to whom this emotion is a stranger, who can no longer pause to wonder and stand rapt in awe, is as good as dead: his eyes are closed.’
(Albert Einstein, 1879–1955)