Details: This poster is of a vintage ad by Theophile Steinlen. It shows a young girl (his daughter Colette), as she carefully tastes the milk she's giving the family cats, to make sure it isn't too hot for them. The three cats look at her expectently. At the top it says Lait pur Sterilise de la Vingeanne.
Theophile Alexandre Steinlen, frequently referred to as just Steinlen (November 10, 1859 - December 13, 1923), was a Swiss-born French Art Nouveau painter and printmaker. Steinlen was befriended by the painter Adolphe Willette who introduced him the artistic crowd at Le Chat Noir (subject of his most famous work) that led to his commissions to do poster art for the cabaret owner/entertainer, Aristide Bruant and other commercial enterprises.