Sentence:  What is more, they are protected from even such discomfort as the dislike of his prisoners may cause to a gaoler by the hypnotism of the convention that the natural relation between husband and wife and parent and child is one of intense <WSD>affection</WSD>, and that to feel any other sentiment towards a member of one's family is to be a monster. 
Meaning of the word marked with <WSD> tags:  A feeling of love or strong attachment.