THE EFFECTS OF STORAGE OX FRUITS 127 



bulk, and in such cases the amount of evaporation may 

 be calculated. Shrinkage is due altogether to the evap- 

 oration of moisture from the fruit. Where this is great 

 the fruit becomes shrivelled and gives a dry, unattractive 

 appearance when offered for sale. Fruit that has an oily 

 skin does not lose moisture by evaporation so readily as 

 the russeted or dry-skinned fruits. 



The amount of evaporation varies greatly with the 

 different varieties and at the different degrees of tem- 

 perature at which it is stored. Under normal conditions 

 it will be necessary to make an average allowance of 5 

 to 10% lost weight for the storage season. Buyers usu- 

 ally estimate from 10 to 15% to be on the safe side and 

 allow for the maximum shrinkage. The only way to 

 prevent undue shrinkage is to pay more strict attention 

 to the humidity of the air in the storage room. Mention 

 has been made of the amount of humidity necessary for 

 the best keeping of the fruit. Where the moisture con- 

 tent of the air or humidity is below 80% a large amount 

 of shrinkage may be expected. On the other hand, even 

 though maintained at the best known standard, 5 to 10% 

 must still be allowed where fruit is stored for a full 

 season. 



Decay in Storage. There are a number of different 

 kinds of rots caused by various forms of fungus growth 

 which are always associated with the storage of fruit. 

 These rots are usually designated by their peculiar ef- 

 fect upon the fruit itself. For example, the most com- 

 mon are the soft rot, the black rot, the brown rot, the 

 bitter rot and the disease commonly known as the black 

 spot or scab, all taking their name from their character- 

 istic appearance. These are all fungus troubles and, 



