What is the primary subject and story introduced in Chapter 34 of the Shri Sai Satcharitra?

Chapter 34 of the Shri Sai Satcharitra continues the discussion on the glory and power of Udi (sacred ash) from the previous chapter. It serves as an introduction to a story meant to illustrate Udi's miraculous properties. The specific narrative presented is about a doctor from Malegaon whose nephew suffered from a terrible ailment called a bone-cyst, or Hadyavran. As detailed in Chapter 34, this disease was incurable by any available medical remedy, leading the family to eventually seek the help of the great saint in Shirdi, Sai Maharaj, as a final resort.