A permanent scrap-book ties the material together in a way that may prove embarassing. Suppose, for instance, that you are keeping printed material from three clubs in your town, as you ought. Clubs seldom do this for themselves. Several St. Louis women’s clubs have told us that they visit the library when they want to indulge in research into their own past doings. It might be natural to keep a scrap-book for each club and insert the material as it comes. But suppose you desire to display all your material on war activities and that some of the material in these scrap-books falls under this head. You will have to leave it out or tear out your scrap-book leaves. Mounting takes time, and it is not necessary to mount everything. Material used only occasionally may be left unmounted. For instance, much newspaper-clipped material may be kept loosely in heavy manila envelopes. Again, some material may be made more accessible if not mounted, especially if in card form and in standard sizes. Such is the postal card. The amount of valuable material obtainable in postal-card form will astonish those who have not looked into the matter. Besides the usual views of localities, embracing buildings, monuments and scenery, good collections of sculpture, architecture, portraits and many other things may be made in postal-card form. Postal cards are all of the same size and very compact, so that they may be filed in trays and treated very much like catalogue cards, guides being used with them as in an ordinary catalogue. The amount of usable material that can be stored to the square foot in this form is probably greater than any other. In all material of this sort, the similarity of collection, treatment and use may be so close that the passage from the picture to the object seems almost negligible; yet many persons apparently consider that here we must draw the definite boundary line between the collections of the library and those of the museum. They would say for instance that it is perfectly legitimate for a library to acquire, preserve and use a plate bearing a printed fac-simile in natural colors, of a piece of textile goods, but not a card mount bearing an actual piece of the same goods, although the two were so similar in appearance that at a little distance it would be impossible to tell the colored print from the actual piece of textile. Librarians will not be apt to attach much importance to this distinction, and those whose collections include treatises on textiles with colored plates will not hesitate to supplement them with mounted specimens of the actual textile with typewritten descriptions. Generally manufacturers are only too happy to furnish samples of their current output, and older specimens, sometimes of historical interest, can be bought from dealers.