needed, and
find it there.

The burden upon the memory that this elaborate system of old must have
entailed is now transferred to the card catalog. This invaluable modern
device is a system for recording upon cards of a certain uniform size
the items and lists and notes to be remembered and preserved, and of
classifying them carefully for ready reference. These cards are stood up
in a closely packed row, in a box or drawer, or in a compartment made
especially for the purpose, where they are arranged alphabetically or by
subjects, in such a way as to be easily run over by the finger till the
desired card is found. The cards must be made of stiff paper or
card-board; they must be accurately cut to a required measure, usually
five inches wide by three inches tall, and they must be fitted exactly
into the box, with "guides" to aid in finding the main subjects. The
"guide" is a card of a different color from the others, usually yellow,
and has a little top extension, so that when the guide is put in its
place in the row of white cards, this top extension will stand up above
the others so as to catch the eye readily. On this little bit of the
guide that stands up above the rest, a main heading is written very
clearly in fine lettering,--or, better, printed neatly--and on all the
cards that are selected to be slipped in behind that guide are written
the notes or references on subjects that belong under that heading. For
instance, suppose the main heading, written on a certain guide, should
be this: "Recipes." Then each card that follows that guide would have
written on its face the details of some recipe--one recipe to one card.
And all the cards on which the housekeeper had written the recipes she
wished to preserve would be placed behind that guide. Then whenever she
wished to use any one recipe, she would open her drawer, look along the
tops of the cards until she found the guide extension--the little
projecting piece that had the word "Recipes" on it. Behind that guide
she would find all her recipes; then it would be but the work of an
instant to pick out the one she wanted. On each separate card would be
written in the upper right-hand corner, the name of the recipe on that
card. If the housekeeper had a great many recipes, she might make more
guides: one for cake recipes, one for bread, and so forth.

Then there would be still other main heads. One might be marked
"Inventory." One might be called "Clothing." Records of