who is Redpenny

Redpenny is a medical student and all-round dogsbody for Dr. Ridgeon. He acts in the capacity of the doctor's laboratory assistant as well as dealing with his voluminous correspondence. The latter is a particularly onerous responsibility given the enormous demand for the doctor's revolutionary new cure for tuberculosis. Redpenny is somewhat immature and idolizes Dr. Ridgeon, believing him to be a scientific genius. As such, he's more than willing to perform any little task for his hero, no matter how menial or tedious.
Though a very minor character in the play, Redpenny epitomizes the unthinking hero-worship often bestowed upon doctors and men of science, especially in the late 19th and early 20th centuries. Society has given Dr. Ridgeon the responsibility to determine precisely who should and should not receive the new cure for tuberculosis he's developed. The doctor's effectively been given the right to play God, and Redpenny is one of his most devoted worshipers.