Blumenthal began an apprenticeship as a sculptor in stone in 1920 and attended evening classes at the Folkwang-Schule in Essen for five years. From 1925 to 1931 he continued his studies at the Kunsthochschule in Berlin. His earliest sculptures, mainly torsos, reveal the influence of his teacher Edwin Scharff, although even as a student he had developed a recognizable style, specializing in very slender youths in expressive rather angular poses. These gentle human figures share the qualities of Wilhelm Lehmbruck's late male figures. He died in Russia during the war.