Excerpt from the report Introduction: The purpose of this study is to compare in some detail results of the use of the two principal methods of packing and shipping lettuce: (1) Shed ice-pack of 4 or 5 dozen heads, and (2) field dry-pack in cartons of 2 or 2½ dozen heads, vacuum-cooled. Although there are several other variations, this study is confined to these two most widely used methods of packing.