The Picture of Dorian Gray Chapter 12
Many years later, when Dorian is thirty-eight years old, he runs into Basil on the street after having not seen him for ages. He is filled with fear and pretends not to recognize Basil, but Basil sees him and catches up with him, saying there is something important he needs to ask. He has been on his way to catch a train to Paris for six months or so, but wanted to find Dorian first, before he left. They go inside Dorian's house, and Basil asks about all of the rumors that have been going around about Dorian's character. There are many people who will not be in the same room as him, and many people who have been apparently corrupted by him and led into a life of sin and shame. Basil doesn't want to believe the rumors, but has to ask Dorian.
Dorian becomes upset with Basil and asks him how he is to blame for these other people's descent, but Basil goes on. He just wants Dorian to deny everything, because then he would believe him and be quieted. He says that the only way for sure is to see Dorian's soul, which is something only God can do.
Dorian laughs and says that Basil can see his soul tonight. Basil says this is impossible, but Dorian tells him this: "I keep a diary of my life from day to day, and it never leaves the room in which it is written. I shall show it to you if you come with me." Chapter 12, pg. 174 Basil follows him.