Karenin seals the compartment

Outwardly nothing has changed; Karenin is merely busier and rather colder, and has never returned to the subject since the night of Betsy's party. His attitude is that of a man who, having failed to put out a fire, tells it to go on burning, and he does not see the insanity of it because he has closed, locked and sealed the compartment of his soul containing his family. He is cold to Serezha too, addressing him as 'young man', and invents work to keep that compartment shut. When Lydia Ivanovna hints at the undesirability of Anna's intimacy with Betsy and Vronsky he stops her severely and then avoids her; he does not see that Society looks askance, does not ask why Anna insists on Tsarskoe Selo where Vronsky's regiment is. Yet without proofs he knows he is a wronged husband and is profoundly unhappy. His doctor finds his liver enlarged and tells Slyudin that a cord strained to its utmost snaps under the weight of a finger.

Tolstoy gives the whole chapter to a man not thinking about something, which is harder to dramatise than thought and is done here through his diary: invented work, avoided friends, a third person always present. The doctor's slack cord is the only diagnosis in the novel that proves exact. Karenin's old question about other deceived husbands is quoted back at him and left unanswered.