[Grmek, the "thunderbolt", "thunder-clapp" (as testimony)].

The paper details how the author (who was a young physician) met, ... by a mere chance. Prof. Grmek a "Sorbonne", in November 1978, how he felt the "Leçons du Jeudi" at the Ecole Pratique des Hautes Etudes (Fourth Section : "Historical and Philological Sciences"). Grmek was both Croatian and French. Other testimonies are given coming from the disciple (who had Prof. Grmek as director of thesis at Paris I - Panthéon - Sorbonne, in 1986) and coming also from Prof. Vera Gavrilovic (Serbia) who met Grmek when he as in "Yugoslavia". Grmek's quotings and photographies, devoted to this exceptional searcher in the field of History of Medicine and History of Sciences, are reported and showed.