Complex sentence: Later, he appears to be searching through a book to inform himself of explanations for ghosts and then by the fireside falls asleep; but he is stirred by his own mind repeating,'Who is this who is coming?'.
Split into simpler sentences: Later, he appears to be searching through a book to inform himself of explanations for ghosts and then by the fireside falls asleep. However, he is stirred by his own mind repeating,'Who is this who is coming?'.