"I don't know how sapient you find most Homines, but I for one find the classification an optimistic misnomer." Book 1, Chapter 1, p. 11.
Mary to Sherlock when he speculates that perhaps his study of bees can be related to the study of people as they are so similar.

"And I thank you, with all my soul, for you have done what my skills could not, and brought back my truest friend from the grave." Book 1, Chapter 2, p. 37.
Watson to Mary at their first encounter.

"Madam, there is no treachery in the truth. There may be pain, but to face honestly all possible conclusions formed by a set of facts is the noblest route possible for a human being." Book 1, Chapter 3, p. 65.
Holmes to Mrs. Barker when she confesses her fears that her husband is a traitor.

"You find even such rustic and unadorned sleuthing satisfying?" Book 1, Chapter 4, p. 96
Holmes...