In the Library of the London Institution, continuous thefts of valuable editions of the classics had occurred. Putting a detective in the library, a young man of suspicious demeanor was soon identified as the thief, and was followed and arrested in the very act of selling a library book. He proved to be a young man of good family, education and previous good character; but the library had suffered such losses from his depredations, that no mercy was shown, and he received and underwent the sentence to two months imprisonment. It may be added as an instance of methods availed of in London to trace missing books, that the librarian, knowing from the vacancies on the shelves what books had been abstracted, printed a list of them, sent it to every second-hand book-dealer in London, at the same time supplying it to the police, who circulate daily a list of missing property among all the pawn-brokers' shops in the city, and recovered all the books within twenty-four hours. The Mercantile Library of Philadelphia missed a number of valuable books from its shelves, and on a watch being set, a physician in the most respectable rank in society was detected as the purloiner, and more than fifty volumes recovered from him. A library at Lancaster, Pa., reported the almost incredible incident of a thief having hidden under his coat, and carried off, a Webster's Unabridged Dictionary! In most cases of detected theft or mutilation of books, strong appeals are made by the culprit or his friends to save exposure by public prosecution. These are commonly, in the case of persons in very respectable circumstances in life, not so much to avoid paying fines imposed by law as to avoid the disgrace attached to publicity, and the consequent damage done to the character of the individual. It is probably true that in a majority of cases, such influences have been strong enough to overcome the determination of the librarian or library authorities to let the law take its course. Now, while it must be admitted that there is no rule without some valid exception that may be made, it is nevertheless to be insisted upon that due protection to public property in libraries demands the enforcement of the laws enacted to that end. The consequence of leniency to the majority of book thieves would be not only an indirect encouragement to the culprits to continue their depredations, but it would also lead to a lax and dangerous notion of the obligations of readers, and the sacredness of such property, in the public mind. Enforcement of the penalties of wrong-doing, on the other hand, tends unquestionably to deter others, both by the fear of publicity which must follow detection, and by terror of the penalty which is or may be imprisonment for a considerable term, besides the imposing of a fine.