>You perceive, now, that these things are all impossible except in a dream. You perceive that they are pure and puerile insanities, the silly creations of an imagination that is not conscious of its freaks—in a word, that they are a dream, and you the maker of it.

Mark Twain

https://en.wikipedia.org/wiki/Heart_of_a_Dog

The story of turning dog into a man by transferring a part of the human brain