Dr. Kerr first appears in chapter 10 on page 70 of the novel. Eliza and Mattie's grandfather bring him to the house to help Mattie's sick mother. He is described as a small, educated man from Scotland.
Mattie tells him that Mr. Rowley told him that his mother has Autumnal fever and he has done everything Mr. Rowley told him to do. Dr. Kerr says that Mr. Rowley is a “damned fool.” He says she doesn't have Autumnal fever, but Yellow fever and that he must bleed her if she is to live. “Bleeding is the only way to save a patient this close to the grave.” He takes 10 ounces of blood from her and says he will be back the next day to take ten ounces more.
Though Dr. Kerr appears bad tempered at first, Mattie soon realizes it is because of the desperate situation his mother and everyone else in the city is in. At the end of his visit, Dr. Kerr recommends that Matilda and grandfather should leave for another town. They want to take mother with them, but Dr. Kerr states that “no town will let her in.”