In the story of Narayanrao's friend, who was stung by a scorpion and what did Narayanrao use as a substitute for Udi?

Chapter 33 narrates an incident where a friend of the devotee Narayanrao was stung by a scorpion and was suffering from severe agony. Narayanrao searched for Baba's Udi to apply to the sting but could not find any. In this moment of urgency, he turned to a picture of Baba and prayed. He then noticed the ash from burnt incense sticks that had fallen at the bottom of the picture frame. Considering this ash to be Udi, he applied a pinch of it to his friend's sting while chanting Sai's name, and the pain immediately subsided, showing the power of faith.