That was why he did not know other little boys.

Again--for the mysterious reason--people did not care that their children should associate with him.

How did he discover this?
He never knew exactly.

He realised, however, that without distinct statements, he seemed to have gathered it through various disconnected talks with Brough.

She had not remained with him long, having "bettered herself" greatly and gone away in glum satisfaction, but she had stayed long enough to convey to him things which became part of his existence, and smouldered in his little soul until they became part of himself.