Earthworm Tractors is a 1936 American film directed by Ray Enright and starring Joe E. Brown and June Travis. The film is also known as A Natural Born Salesman in the United Kingdom.This film is based on characters created by William Hazlett Upson. He wrote stories for Saturday Evening Post and introduced Alexander Botts, A Natural Born Salesman, and The Earthworm Tractor Company (based on his previous work with Caterpillar Tractors) in 1927 which lasted until his death in 1975.