Marcus Welby, M.D.

Dinty Gallagher refuses to give up his regimen of diet pills and steam baths, even after having fainting spells. Gallagher's desperate attempts to make the weight for the most important race of his life result in physical collapse and he is hospitalized. There he overhears Doctors Welby and Kiley tell his manager that tests indicate he is still growing, at 21, and that it will be impossible for him to continue his career as a jockey.