For classification, envelopes can be used or manila cards 10x12 inches. The teacher, parent, or advanced student will probably think the envelope most useful because most easily carried and filed,--most likely to be used. But clippings should be bound together in orderly appearance, or else it will be disagreeable working with them. Children, however, will like the pasting on sheets, which show clearly the growth of each topic. Envelopes or cards should not have clippings that deal with only one health topic. Unless a test is made to see how many health references there are in a given period, it should be made a rule not to clip any item that does not contain something new,--some addition to the knowledge already collected. Advertisements will prove interesting and educative. When newspapers and magazines announce some new truth, the commercial motive of manufacturer or dealer sees profit in telling over and over again how certain goods will meet the new need. Children will soon notice that the worst advertisements appear in the papers that talk most of "popular rights," "justice," and "morality." They will be shocked to see that the popular papers accept money to tell falsehoods about fake cures. They will be pleased that the best monthly magazines contain no such advertisements. They will challenge paper or magazine, and thus will be enlisted while young in the fight against health advertisements that injure health. To clip articles from magazines will seem almost irreverent at first. But the reverence for magazines and books is less valuable to education than the knowledge concealed in them. Except where families preserve all magazines, clippings will add greatly to their serviceability. The art of cross-referencing is invaluable to the organized mind. The purpose of classifying one's information is not to show how much there is, but to answer questions quickly and to guide constructive thinking. A clipping that deals with _alcoholism_, _patent medicine_, and _tuberculosis_ must be posted in three places, or cross-referenced; otherwise it will be used to answer but one question when it might answer three. If magazines may not be cut, it will be easy to record the fact of a useful article by writing the title, page, and date on the appropriate index card, or inclosing a slip so marked in the proper envelope.