The Back Bay district is the section of Boston where are located the residences of the rich, and it is quite exclusive.

“I guess I can find the place, sir,” said Tom confidently, though he had only been in the locality a few times.

“Well, here is your car fare. Be careful of the books now, as some of them are quite expensive. Be on hand early in the morning.”

“Yes, sir,” answered Tom, as he put on his overcoat, and with the bundle of books, which were quite heavy, he started off.

He was soon in the Back Bay district, and a little inquiry enabled him to find the doctor’s house.

“My, it’s a big place!” exclaimed Tom. “He must have money to live in a house like that.”

He went up the front steps and rang the bell. The door was presently opened by a woman, and, in the light that streamed out into the darkness from the hall, Tom saw that she was about middle age, and that her features were rather sharp and hard. Her face was not made more attractive by the way her hair was arranged, for it was drawn tightly back on both sides of her head.

“Well, what do you want?” she asked snappishly. “We don’t want to buy anything, and if you’re the boy from the grocery you’re too late with the stuff, and you must go round to the back door. I can’t have tradesmen coming to the front door.”

“These are some books Dr. Spidderkins purchased to-day,” replied Tom. “I brought them, because the expressman forgot to call.”

“What’s that? Books?” asked a voice from within, that the boy recognized as the doctor’s. “Who has books for me?”