Read it through once

He solicited the society of no one more. At dusk he went into his chamber. Through the whole night, and far into the morning, we heard him groaning and murmuring to himself. Hareton was anxious to enter; but I bid him fetch Mr. Kenneth, and he should go in and see him. When he came, and I requested admittance and tried to open the door, I found it locked; and Heathcliff bid us be damned. He was better, and would be left alone; so the doctor went away.