In the novel, Bradbury tells us that books are incorporated into our souls, and change our very being. The Hound is programed to detect the unique chemical “fingerprint” of an individual, down to a biochemical and cellular level. Beatty has already begun to suspect that Montag is changing his thoughts. He is beginning to suspect that Montag is growing suspicious of the concept that books cause confusion, and must be destroyed. Bradbury shows us that when we change what we read, think, and do, it can change us down to the cellular level. Unfortunately, the Hound is already beginning to detect this change in Montag.