 What can we infer from the passage that caused Mr. Higgins to go crazy?
As the police reconstructed it later, Mrs. Higgins had attempted to awaken him on the third morning at seven-thirty, suggesting that he really ought to stop being so foolish, and go back to work. Mr. Higgins, it was learned later, had suddenly erupted from his bedroom, brandishing a .30-.30 hunting rifle and, being annoyed at the shrieks of his wife and sister, had fired seven shells at them, killing his wife on the spot and wounding his sister in the hand and shoulder. Higgins used his own good lungs to shout obscenities back and challenge anyone present to hand-to-hand combat.
 He had flunked an exam and was overwhelmed with stress.
 He was no longer happy with his wife hence why he murdered her.  He was tired of his job and didn't want to return.  He was overly tired and delirious.  He had flunked an exam and was overwhelmed with stress.