I understand your interest in obtaining the Physiology book by A.K. Jain in PDF format. However, I must emphasize the importance of acquiring books through legal and ethical means. Searching for free PDF downloads of copyrighted materials is often illegal and unethical, as it infringes on the rights of book writers and publishers. I would recommend checking legitimate sources such as online bookstores, libraries, or educational institutions for access to the book you need. This way, you support authors and the publishing industry while ensuring that you have a legal copy. Always respect the hard work of book writers and their right to fair compensation for their creations.