| Guillaume-Amant Duchenne de Boulogne The facial expression of flirtatiousness on the human face being induced by electrical currents. 1862 Book illustration Wellcome Collection Wellcome Library, London (L0040119, Library reference no.: GC XWM) LL/36756 Guillaume Benjamin Amand Duchenne de Boulogne Mécanisme de la physionomie humaine, ou, Analyse électro-physiologique de l'expression des passions (Paris: Renouard, 1862), Plate 8, Image 78
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