When the pages of a 19th century book are falling out, this usually means the sewing has failed. The thread holding the leaves of each signature together has broken or the cords holding the signatures together have been broken. In either case, the book must be disbound so it can be resewn. After the cover is removed, the spine is cleaned of all adhesives and linings then each signature is separated from the next. Often times the signature folds must be repaired before resewing. A sewing frame is used to hold the cords in a vertical position while the thread is sewn through each signature and around the cords. The sewing process can take several hours, depending on how thick the book is and how many signatures it has.