Answer:
In chapter 9 of Dr. Jekyll and Mr. Hyde, Dr. Lanyon's Narrative, Dr. Lanyon is a friend and colleague of Dr. Jekyll and Mr. Hyde. The chapter begins with Dr. Lanyon receiving a letter from Dr. Jekyll, in which Jekyll asks Lanyon to perform a favor for him. Lanyon is hesitant, but ultimately agrees to do as Jekyll asks.
The favor involves delivering a letter and a small vial of a mysterious potion to Mr. Hyde. Lanyon is instructed not to open the letter or examine the contents of the vial. When Lanyon delivers the items to Mr. Hyde, he is shocked by the transformation that takes place before his eyes. Mr. Hyde drinks the potion and transforms into Dr. Jekyll.
Dr. Jekyll then explains to Lanyon that he has been using the potion to transform between his two identities, and that the transformation is irreversible. Jekyll also reveals that he is dying and that he has written a full confession of his actions, which Lanyon is to publish after his death.
The chapter ends with Dr. Lanyon's reflections on the events that have transpired and his shock and disbelief at the revelation that Jekyll and Hyde are one and the same.
Step-by-step explanation: