quality:correction, linguistic:translation
Hanna-Barbera era (1940–1958)

After MGM gave the green-light for Hanna and Barbera to continue, the studio entered production on the second Tom and Jerry cartoon, The Midnight Snack (1941). The pair continued to work on the series for the next fifteen years of their career. The composer of the series, Scott Bradley, made it difficult for the musicians to perform his score which often involved the twelve-tone technique developed by Arnold Schoenberg. The series developed a quicker, more energetic and violent tone which was inspired by the work of MGM colleague Tex Avery. Hanna and Barbera made minor adjustments to Tom and Jerry's appearance so they would "age gracefully". Jerry lost weight and his long eyelashes, while Tom lost his jagged fur for a smoother appearance, had larger eyebrows, and received a white and gray face with a white mouth. He adopted a quadrupedal stance at first, like a real cat, to become increasingly and almost exclusively bipedal.