Max Planck bronze portrait

Metal (probably bronze) profile portrait of Max Planck mounted on black marble. The bronze plaque is incised with the date "MCMXXXI" to the right of the head, as well as "MAX PLANCK" below the head and the artist's signature at the base of the subject's neck. The artist's name isn't clear, but appears to say: "A. LOWENTHAL." Arthur Immanuel Lowenthal was an artist of Austrian origin who lived from 1879-1964, and other work by him is very similar to this piece. The verso of the piece has a brass stick stand as well as a hook.