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Leonard Jongkees "a professor for 25 years, how quickly time passes!" I vividly remember an incident just after World War II. Gunnar Holmgren had been invited by his friend Burger to deliver a lecture on fenestration in Amsterdam. At the time this was a very current subject. When the opportunity for discussion arrived there was a period of silence because of an obvious anticipation by those in the audience over who would be the first to speak: old Burger, or the host De Kleyn, or perhaps Van Gilse—at that moment the oldest practicing professor in the Netherlands. But no, it was young Jongkees, who broke the somewhat awkward silence. He made a good remark, but it raised some astonishment.
In his younger years Jongkees often unexpectedly took the floor, and he loved to act as the "enfant terrible." He certainly had something of the frolicsome exuberance of a "puppy," as