Who is The Doctor from Short Story Masterpieces and what is their importance?

The Doctor is a character in the story, The Use of Force. He is a caring young man, who is tainted by his recent dealings with diphtheria taking the lives of local children. When he encounters a young girl who refuses to be looked at, his anguish over the lost children boils over, and he uses more force than necessary. While he admits the child must be looked after, for her own safety and the safety of others, he also realizes that he enjoys the struggle, which to him symbolizes the struggle against the disease itself.