You will perhaps attach but small importance at first thought, to the next insidious foe to library books that I shall name-that is, wetting by rain. Yet most buildings leak at the roof, sometime, and some old buildings are subject to leaks all the time. Even under the roof of the Capitol at Washington, at every melting of a heavy snow-fall, and on occasion of violent and protracted rains, there have been leaks pouring down water into the libraries located in the old part of the building. Each of these saturated and injured its quota of books, some of which could only be restored to available use by re-binding, and even then the leaves were left water-stained in part. See to it that your library roof is water-tight, or the contents of your library will be constantly exposed to damage against which there is no insurance.
Insects and Vermin
Another besetting danger to the books of our libraries arises from insects and vermin. These animated foes appear chiefly in the form of book-worms, cockroaches, and mice. The first-named is rare in American libraries, though its ravages have extended far and wide among the old European ones. This minute little insect, whose scientific name is the anobium paniceum, bores through the leaves of old volumes, making sometimes holes which deface and mutilate the text. All our public libraries, doubtless, have on their shelves old folios in vellum or leather bindings, which present upon opening the disagreeable vision of leaves eaten through (usually before they crossed the sea) by these pernicious little borers. It is comforting to add, that I have never known of any book-worm in the Congressional Library-except the human variety, which is frequently in evidence. Georgetown College library once sent me a specimen of the insect, which was found alive in one of its volumes, but the united testimony of librarians is that this pest is rare in the United States. As to remedies, the preventive one of sprinkling the shelves twice a year with a mixture of powdered camphor and snuff, or the vapor of benzine or carbolic acid, or other repellant chemicals, is resorted to abroad, but I have not heard of any similar practice in this country. I may remark in passing, that the term "book-worm" is a misnomer, since it is not a worm at all, but an insect. A more serious insect menace is the cockroach, a hungry, unclean little beast, which frequents a good many libraries, and devours bindings (especially fresh ones) to get at the paste or savory parts of the binding. The remedy for this evil, when once found to exist, is to scatter the most effective roach poison that can be found, which may arrest further ravages.
Another insect pest is the Croton bug, (Blatta Germanica) which eats into cloth bindings to get at the sizing or albumen. The late eminent entomologist, Dr. C. V. Riley, pronounced them the worst pest known in libraries, but observed that they do not attack books bound in leather, and confine their ravages to the outside of cloth-bound books, never troubling the leaves. The remedy prescribed is a powder in which pyrethrum is the chief ingredient, sprinkled about the shelves.
Among the rodents, mice are apt to be busy and mischievous infesters of libraries. They are extremely fond of paste, and being in a chronic state of hunger, they watch opportunities of getting at any library receptacle of it. They will gnaw any fresh binding, whether of cloth, board, or leather, to get at the coveted food. They will also gnaw some books, and even pamphlets, without any apparent temptation of a succulent nature. A good library cat or a series of mouse traps, skilfully baited, may rid you of this evil.
The injury that comes to library books from insufficient care in protecting them on the shelves is great and incalculable. There are to be seen in every library, volumes all twisted out of shape by the sagging or leaning, to which the end-book is subjected, and which is often shared by all its neighbors on the shelf. The inevitable result is that the book is not only spoiled in its good looks, but (which is vastly more important) it is injured in its binding, which is strained and weakened just in proportion to the length of time in which it is subjected to such risks. The plain remedy is to take care that every volume is supported upright upon the shelf, in some way. When the shelf is full, the books will support one another. But when volumes are withdrawn, or when a shelf is only partly filled with books, the unsupported volumes tumble by force of gravitation, and those next them sag and lean, or fall like a row of bricks, pushing one another over. No shelf of books can safely be left in this condition. Some one of the numerous book-supports that have been contrived should be always ready, to hold up the volumes which are liable to lean and fall.