22 THE APPLE IN COLD STORAGE. 



wall. Apples placed near the refrigerating pipes or near the cold-air 

 duct where it enters the room maybe injured by freezing if the plant 

 is improperly installed or managed; or if the piping or air circulation 

 is faulty, the temperature at the bottom may be lower than that at the 

 top of the room. 



The frosting of the fruit does not necessarily injure it. When the 

 apple freezes, the water in the cells is withdrawn and frozen in the 

 intercellular spaces, and if it thaws slowly and the freezing has not 

 been too severe, the cells may regain the water without injury and 

 resume their living function. If the thawing' is rapid, the cells may 

 not reabsorb the water with sufficient rapidity, and in this case it 

 remains in the intercellular spaces and is lost by evaporation. In 

 addition, the tissues next to the area of greatest freezing ma}^ be 

 forced apart by the formation of ice crystals in the intercellular spaces. 



If the freezing is so severe as to withdraw too much of the cell 

 water, the cells may not be able to absorb it and will be killed in the 

 same manner as if dried out in any other way. Occasionally the 

 freezing is so rapid that besides the withdrawal of water the cell con- 

 tents are disorganized or possibby frozen outright; at any rate, the 

 cell may be directly killed by a sudden change of temperature. It 

 is probable that varieties may differ as to the degree of freezing they 

 will stand without injuiy, and further, that the same sort may vary 

 in this respect when grown under different conditions or subjected 

 to different treatment. 



The most characteristic results of injurious freezing are a translu- 

 cent appearance of the skin of the fruit, a water-logged and springy 

 or spongy condition of the flesh, a forcing apart of the tissues, and a 

 brownish discoloration of the flesh. The browning may result from 

 any cause which results in the death of the cells and is not necessarily 

 characteristic of freezing. It often happens that the skin of the fruit 

 retains its normal brightness after the interior has discolored. 



In -the practical handling of frozen stock, the temperature should be 

 raised very slowly until the frost is withdrawn. If possible, the fruit 

 should not be moved until it is defrosted, as it discolors quickly wher- 

 ever a slight bruise occurs or even where the skin is lightty rubbed. 

 With these precautions observed it is often possible to defrost stock 

 that is quite firmly frozen without apparent injury to it. 



INFLUENCE OF A FRUIT AVRAPPER. 



In the storage investigations under discussion a comparison has been 

 made between wrapped and unwrapped stock on the keeping quality 

 of the fruit, and the efficiency of different kinds of paper for wrap- 

 pers — tissue, parchment, waxed or paraffin, and imprinted news — has 

 been tested. A box of unwrapped fruit, with packages of fruit 

 wrapped with the kinds of paper mentioned in order above, is shown 

 in Plate III, fig. 1. 



