“U.S. No. 1” consists of pears of one variety which are mature, but not over-ripe, carefully hand-picked, clean, fairly well formed, free from decay, internal breakdown, scald, freezing injury, worm holes, black end, and from damage caused by hard end, bruises, broken skins, russeting, limb- rubs, hail, scars, drought spot, sunburn, sprayburn, stings or other insect injury, disease, or mechanical or other means. (See §§51.1265 and 51.1268.)