10 BULLETIN 63, U. S. DEPARTMENT OF AGRICULTURE. 
during the winter and early spring months, when the prevailing outdoor temperature 
is low, so low at times that the problem has been to protect the fruit from freezing rather 
than to reduce its temperature by artificial means. During periods of extremely cold 
weather refrigeration may be a distinct disadvantage rather than otherwise. With the 
present refrigerator-car equipment, the insulation provided to keep the fruit cool 
during transit must also be relied upon to protect the fruit from freezing. This it does 
by retarding the cooling of the fruit and reducing its temperature very slowly, thus 
enabling the car to reach the market before the contents are actually frozen. It is easy 
to see that the length of time required to cool the fruit to an injurious extent depends 
upon (1) the outdoor temperature, (2) the efficiency of the insulation of the car, and (3) 
the temperature of the fruit at the time the car encounters extreme weather conditions 
in the North. 
The present-day refrigerator car is only partially efficient during extreme weather. 
There are many types of refrigerator cars with varying insulation, but none are able 
to withstand extreme cold for any considerable length of time without the use of 
artificial heat, just as they are unable to keep the contents cool in hot weather with- 
out the use of ice. It follows, then, that under ordinary conditions during cold 
weather fruit which has been cooled by the use of ice during the early part of the 
trip from Florida will be more liable to injury from freezing than fruit which has not 
been so cooled before it is subjected to extremely cold weather. The appreciation of 
this point is of great importance in discussing the refrigeration of Florida oranges, 
because a very large proportion of the crop is moved during periods of excessively 
cold weather in the North, although the temperature in Florida may be sufficiently 
high to warrant the use of ice at the beginning of the trip. 
The investigations of the Bureau of Plant Industry have amply demonstrated that 
Florida oranges may be transported to market under ventilation with a minimum 
loss from decay, even during periods of warm and humid weather, if sufficient care is 
used to preserve the skin of the fruit in a sound, unbroken condition. None of the 
experimental shipments commented upon in this paper were refrigerated. The use 
of refrigeration during transit to market must not be considered as a means to offset 
the effects of rough or careless methods of handling. Icing can not permanently 
prevent deterioration. The low temperature only temporarily arrests the develop- 
ment of the decay fungi. As soon as the fruit has been unloaded in market it warms 
up, and decay develops very rapidly if a considerable number of the oranges have 
been injured by careless handling. As a result such fruit soon gains a reputation for 
very poor market-holding qualities. It is as important to have the fruit reach the con- 
sumer in good condition as it is to have it arrive in the market sound. 
A considerable number of shipments were iced during the season of 1912-13, 
especially during January and during a later period of warm, humid weather, when 
heavy decay developed in nearly all shipments. It is safe to say that the number of 
cars handled under refrigeration during this season was greater than during all pre- 
vious seasons together. Many of the shippers claim that they have been able to 
place the fruit on the market in much better condition when shipped under refriger- 
ation than when shipped under ventilation only. This conclusion is based upon a 
comparison of iced and noniced shipments. It is probable, however, that the com- 
parison was not always fair, for the reason that no systematic study was made of the 
behavior of fruit of the same grade and quality under the two systems of shipment. 
Nevertheless, the general opinion prevails among growers and shippers that icing has 
resulted in material benefit to the fruit and has yielded increased returns. Refriger- 
ation, therefore, bids fair to become an important factor in the handling and ship- 
ment of the Florida citrus crop. 
During the past season, with its periods of excessively high decay, the Florida 
Citrus Exchange strongly urged its members to move their fruit north under refriger- 
ation. The recommendations of the exchange officials, in brief, provided (1) that the 
