"if anyone knows, it will be Lanyon," he had thought
Reader is established to be trusting Lanyon
"[Lanyon] was a hearty, healthy, dapper, red-faced gentleman, with a shock of hair prematurely white and a boisterous and decided manner"
Contrasts to the presentation of his character in Chapter 6
Presented as a healthy and optimistic man
"At sight of Mr. Utterson he sprang up from his chair and welcomed him with both hands"
Warm and inviting welcome
Traditional - links to his view of science and the traditional sense of a Victorian gentleman, polite
"Henry Jekyll had became too fanciful for me"
Lanyon is presented as conventional and traditional man of science
Jekyll wants to break free of the convention and tradition, Lanyon sees this as unrealistic
"Such unscientific balderdash"
Lanyon views Jekyll's scientific discoveries as unexplainable and nonsense
"would have estranged Damon and Pythias"
Damon and Pythias was an ancient greek story about two inseperable friends
Oxymoron implying the deep and irreparable rift between Lanyon and Jekyll
Chapter 6
"He had his death-warrant written legibly upon his face"
Foreshadows Lanyon's death
"[Lanyon] had grown pale; his flesh had fallen away; he was visibly balder and older; and yet it was not so much these tokens of a swift physical decay"
Lanyon depicted as sickly, vulnerable and weak with physical decay having connotations of death, foreshadowing his death