Describe the unique 'remedy' Sai Baba gave to Amir Shakkar for his rheumatism and the principle behind it.

For Amir Shakkar's severe rheumatism, Sai Baba prescribed a remedy that was not a physical medicine but a test of faith and endurance. Chapter 22 explains that Baba's only medicine was His word. He commanded Amir to stay steadily in the dilapidated and damp Chavadi, a place with conditions contrary to healing joint pain. Baba's firm words were that Amir should not weigh the negative factors like wind, rain, or dampness. The principle was that accepting Baba's word as the ultimate medicine, despite all external hardships, was the key to healing. Amir's internal faith was paramount, and by accepting the command, his faith was being tested and strengthened.