Enhanced descriptions from Syndetics:

The joining of words and pictures in advertising art is nowhere more intimate than in mortised cuts. This printer's term refers to designs, usually pictorial, engraved on wood, or stereotyped in metal from wood blocks, with one or more hole sawn into the plates so type could be inserted. Less strictly, it applies to the images printed from such cuts. In some 19th-century specimen books, the word "pierced" is used as a synonym for "mortised."
These cuts, perhaps more than any other genre of advertising art, conveys a period feeling so distinctive that they are among the most-sought-after graphic elements from 19th-century sources. For all their popularity, both then and now, these cuts are widely scattered through files of old periodicals and typefounders' and engravers' catalogues. The present collection represent an extensive search through rare printed materials too numerous to list here.
The collection features 551 of the most interesting and versatile images, arranged in categories. Anyone who has tried to find a vaguely remembered cut in one of the old specimen books, in which cuts were usually arranged haphazardly, will appreciate this organization, especially considering the sheer number of designs contained in the book. It is probably the largest and most varied compendium exclusively devoted to this genre of wood-engraving available today.