Can you tell me the story from Chapter 34 about the doctor's nephew and the power of Udi?

Certainly. Chapter 34 of the Shri Sai Satcharitra narrates the story of a degree-holding doctor from Malegaon whose young nephew was afflicted with a severe bone-cyst, also known as Hadyavran. The text highlights that despite the uncle being a physician and consulting other expert surgeons, all medical treatments, both native and foreign, failed to provide any relief. The child was in immense pain. As a last resort, after hearing of the great saint Sai Maharaj in Shirdi, the parents traveled to see him. Upon hearing their plea, Sai Baba, the embodiment of compassion, reassured them and gave them Udi to smear on the wound, promising to remove the ailment.