When your correspondent started his self-imposed task of writing a suitable contribution in honour of G. van Iterson on the occasion of his diamond membership of our Botanical Society, a task that would otherwise undoubtedly have fallen upon the shoulders of the late and lamented A. J. Kluyver – in Van Iterson’s own words facile princeps among his pupils – two things became clear. To give even only a fleeting survey of the many facets of the phenomenon Van Iterson would require a painstaking study of his many activities and achievements, which will no doubt have to be made some day, but to do him justice this would have taken up more time than your correspondent could possibly spare. To quote Kluyver in his paper commemorating Van Iterson’s 25th anniversary as a professor at the Technical University of Delft, which also hinted at the typical modesty of the celebrator of this jubilee (who declined the suggestion of a proper celebration on account of the economic crisis), in my free translation from the Dutch: “ What a peculiar gathering it would have been if he had agreed to a celebration! There is not the slightest doubt that the venerable city of Delft would have seen within its walls a large assembly of prominent people, but it is just as certain that of these persons it could have been said ‘Bien étonnés de se Irouver ensemble'. (...)• Many have asked for his advice about certain problems and usually received a most useful (but always a courteous! A. M.) answer. However, as a rule it would appear that they would hardly have had any idea about all the other facets of this remarkable scientist because they could not possibly surmise in what fields he has been active". Well, a gathering of exactly this kind, which eventually became a proper manifestation, took place sixteen years later when Van Iterson became emeritus professor. An account of this memorable function by the late Dr. Antonia Kleinhoonte, for many years a close collaborator and personal friend of the parting professor, shows clearly how widely he was honoured and appreciated. These two commemorative papers also give an account of the main “statistical” data such as date of birth (August 19, 1878, at Roermond), his studies at the then Higher Polytechnic School at Delft (1897-1901) to become a chemical engineer, his association with H. Behrens (who introduced him into fibre microscopy and micro-chemistry) and with the world-famous bacteriologist M. W. Beijerinck (whose asistant he became and who, according to the story still circulating in my time, used to introduce him to visitors with the words: “This is my assistant Van Iterson who knows much more than I do”), his thesis (1907) on a subject of his own choosing (a still much-cited “classic” on phyllotaxis) and the creation of a chair of Microscopical Anatomy to be held by Van Iterson, the first greater mile-stone in his career. We can follow its further evolution through the moving into a new laboratory built according to his own specifications in 1917, his chair and laboratory henceforth being referred to as of “Technical (i.e.. Technological) Botany”, his engagements in technological research of rubber, fibre crops, paper, starch, ethereal oils and woods and in tropical agriculture, his organizing talents concerning tropical agricultural research stations in the formerly Netherlands East Indies and the establishment of the Dutch Organisations for Scientific and Industrial Research, his ability as a teacher and his (alas, too few!) achievements as a very thorough research worker. In the meantime he had become a member of the Dutch Royal Academy of Sciences (1918) and of many special or standing committees. This gives us a good idea of his course of life, but – and this is your correspondent’s second consideration – what would Van Iterson like best: a cool and impersonal enumeration of his works and peregrinations or some personal reminiscences? My guess is that since his characteristic modesty makes him depreciate his own great merits (according to his personal admission he loved everything he did just for the sake of doing some decent work and never did anything out of particular ambitions), personal glimpses would sooner hit the right spot. Strangely enough, in spite of all honours bestowed upon him, appreciation of his doings by biologists pleases him more than anything else. Characteristic and sympathetic was his complete surprise and great pride when the Leidse Biologen Club (an organisation of biology students of Leiden University) offered him an honorary membership. When his laboratory attracted a number of advanced students mainly between 1930 and 1942 and mostly from Leiden University (your correspondent being one of them), his knowledge and erudition were a complete revelation to us. His special courses in plant anatomy, in textile and wood microscopy, in ethereal oil analysis and microscopy, and other subjects were of a standard even astonishing to us as advanced students. I have never encountered another person teaching at university level who could, with such apparent ease and with such a penetrating and up-to-date knowledge of each subject, lecture upon a host of subjects ranging from biostatistics and genetics to wood, fibre and paper microscopy, cell wall structure, X-ray diffraction of organic substances, biological membranes, vegetable oils, starch and starch products, economic botany plant physiology and biochemistry. Although we thought we definitely knew something and had some experience, it simply inspired us with awe and sheer admiration. We soon got the impression, however, that he considered us as grown-ups (up to a point at least) and that he took great pain in discussing every phase of our research program, often assisting personally with cutting sections or providing relevant literature. His interest in botany has been manifest since his early days. He most fortunately coupled biology with mathematics and statistics and some of his ingeneously constructed models for demonstrating distributions of populations and correlations are highly instructive. As I had the pleasure of working under his guidance on the problems associated with the shape of cells, I learned to appreciate his knowledge of the mathematical background and, also, his lively enthusiasm when discussing these favourite topics. His membership of the Dutch Botanical Society also bears witness of his active interest in this biological discipline: he was a member of several committees and published in the periodicals of the Society or had papers by pupils published. His modesty is also most manifestly reflected in his refusal to add his name as co-author to papers of which he was a good bit more than just the auctor intellectualis. The honorary membership of our Dutch Botanical Society (K.N.B.V.) bestowed upon Van Iterson in 1957 was greatly appreciated by him. Needless to say he deserved it, not only as an outstanding scientist and author of botanical papers but also on account of his continuous interest in our Society since he joined it as a member in 1909. He once told me he often felt sorry that owing to his many other commitments he could not participate in the activities of the K.N.B.V. as much as he would have desired.