[Apropos of the "Lesson in anatomy"].

Some striking features from the famous lesson of Prof. Tulp are presented: the implication of the spectator in the scene, the unity of the action exalted by the "chiaroscuro", the expression of the movement and of Tulp's personality. In addition, the probable scientific and philosophical underlying thoughts of Rembrandt are discussed having respect to historical data concerning Descartes and Constantin Huygens. The indications given by the lesson of Pr. Deyman about Rembrandt's conception of this subject and the evolution of his art, are then presented. Among the "Anatomy lessons" of the Dutch painting which have preceded and followed those by Rembrandt, the three having particular relevance to the Master are discussed, allowing to better appreciate his originality, his audaciousness and his mastery of his art.