THE EFFECTS OF STORAGE ON 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, 
