William J. Broad in his 2012 book, The Science of Yoga: The Risks and Rewards, calls A Treatise on the Yoga Philosophy "the world's first scientific study of yoga." In it, N.C. Paul investigates human hibernation and the specific yoga practices that make it possible.
A Treatise on the Yoga Philosophy was first published in 1951 by a young Indian doctor in Calcutta. N.C. Paul, who was Indian by birth but Anglicized his name, had witnessed yogis going without food or water in "hibernation" for as long as forty days. He decided to use his training in the scientific research methods of the time to discover what made these feats
possible. His conclusions detail not only specific postures but also eating habits and breathing techniques that slow the metabolism, promote longevity, and make possible feats unknown to the rest of untrained humanity. The book contains two eyewitness accounts of human hibernation conducted under highly supervised conditions.
This 62-page version of A Treatise on the Yoga Philosophy was scanned from the second edition of the book. Its 1882 publication date puts it in the public domain. The book is presented here in its entirety. Obvious errors that were present in the original text (misspellings, etc.) have been marked but not corrected. Scanning errors have been corrected, yielding a clean, faithful digital version of the original text. I have included the original page numbers in the right hand margin for reference purposes.
