Based on Chapter 34, what is the significance of Udi and how is its power demonstrated?

Chapter 34 presents Udi as a substance with divine healing capabilities that transcend conventional medicine. Its significance lies in its power to cure even incurable diseases through Sai Baba's grace. The introduction of the chapter states its purpose is to continue narrating the "greatness of Udi." This power is demonstrated through the story of the doctor's nephew, whose terrible bone-cyst could not be cured by any remedy, including surgery. The belief that brought the family to Shirdi was that if the "great Avaliya applies Udi with his own hand, even incurable diseases perish." Sai Baba's act of giving them Udi to smear on the wound, promising a cure, serves as the primary illustration of its miraculous and pain-uprooting qualities.