By-the-bye

[…] it’s only a ward of Mr. Smallwood’s; he is on his way to Oxford, that is all. A surprisingly clever young man,—oh, by-the-bye, Miss Meadows, we are going to make up a little party on Friday, can you come, and bring your brother, Loftus.

"Ah, by-the-bye, I wanted to ask you about that lady. Does anyone know who she is? My wife is very anxious to find out whether she is—well—er—quite the proper person, you know! When one has young girls, one cannot be too careful."