The word that best describes the author's tone in this excerpt from "That Spot" by Jack London is Indignant.
Explanation:
The excerpt from "That Spot" by Jack London shot a narrative from the character about the memories collected in relation to Stephen Mackaye, but these memories are crumbled down by a feeling of bitterness and regret for all the time, love and effort given to this person who at the end didn't give the same back.
