With these thousand sketches upon fragile clay we can retrace an evolution which lasted four or five centuries, and created the art of drawing, as it is practised by all modern nations. Indeed, after long endeavours, the Greeks were the first who shattered the tyrannic conventions to which artists had conformed, in Egypt, Chaldea and Assyria. They refused to disjoint the human form on the pretext of showing it from a true anatomical point of view. For the artificial reality of the body drawn in sections, they substituted a living silhouette seized in rapid movement, rendered with all its irregularities of form and its lack of symmetry. This proved the victory of art over science. One became accustomed to figures half turned to the spectator, to perspective, to parts half hidden or suppressed, one learnt to consider Nature not as she is, but as one sees her. The orientation of art was completely changed. The invention of foreshortening and of modelling by means of shadows belongs to the Greeks. Both had considerable influence on the Roman world, and later on modern times. We may compare these discoveries to those in physics or in chemistry which entirely revolutionized the domain of science. It is an error to suppose that the scientist alone is capable of discoveries which humanity at large is called upon to enjoy. In art the same action and reaction take place, and a solidarity uniting the past and present is not less powerful. Between an Egyptian fresco and an oil painting by Van Eyck there is scarcely anything in common as regards conception and process. Between a drawing by Douris and the _Stratonice_ of Ingres a resemblance is very perceptible, almost a kind of brotherhood.