536 Journal of Agricultural Research voi. xxvi, no. h 
the sixth or eighth week of storage. During this time the scald-producing 
agencies are apparently most active, yet up to the end of the period it is 
possible to largely or entirely overcome any accumulated tendencies to 
the disease by wrapping the apples in oiled paper or by airing them out 
in a warm room. The second stage in the development of the disease 
extends over a 5 to 8 week period following the first. Preventive meas¬ 
ures have now become of little or no avail. The apples are doomed to 
scald if given sufficient time, yet if removed from storage before the end 
of the period they do not show scald even upon warming. The third 
stage or period covers the remainder of the time the apples are in storage. 
They have now become latently or potentially scalded. Certain skin cells 
are practically dead, yet will remain green and appear practically normal 
if not exposed to warm air. The fourth stage includes the life of the 
scalded apples after removal from storage. The affected skin turns 
brown and completes its death processes. 
SUMMARY 
The results are reported on 67 different apple storage experiments 
carried out under commercial storage conditions. 
Apples packed in the usual unoiled wrappers have had practically the 
same degree of scald as those that were unwrapped. 
Paraffin wrappers have caused considerable reduction in the prevalence 
of scald, but have proved far inferior to oiled wrappers. 
In 63 of the 67 tests the oiled wrappers have either entirely prevented 
the development of scald or reduced it to a degree that made it negli¬ 
gible from the commercial standpoint. The apples in oiled wrappers 
have shown but little if any delay in coloring and have been entirely 
normal in taste and appearance. 
Wrappers carrying less than 15 per cent of oil have been less efficient 
in scald control than those carrying 15 per cent (about 0.28 gm. per 
wrapper) or more of oil. 
Seven different mineral oils have been tested in the oiled wrappers and 
all have been efficient in scald control. 
Oiled blotter material scattered through the barrel package has re¬ 
duced scald to about one-third the amount found in the untreated barrels. 
Oils and mixtures of oils and waxes applied to the skin of the apple 
have given rather erratic results in scald control, the efficiency of 
the treatment usually varying with the amount of oil applied. The 
apples have usually had a greasy appearance and an abnormal greenness, 
sometimes accompanied by a lack of flavor and a general condition of 
the fruit similar to that resulting from storage in high percentages of 
carbon dioxid. 
Various oil determinations are reported, giving the amount of oil in 
the fresh wrappers and in the used ones, the amount taken up by 
box liners; and the amount taken up by unoiled wrappers applied to 
the apples inside the oiled ones. 
The conclusion is drawn that the checking of the changes from green 
to yellow in the skin of the apple is due to the oil actually deposited on 
the apple, and that the extent of the scald control is largely determined 
by the amount of oil in close proximity to the skin of the apple but not 
necessarily deposited on it. 
Four stages, or periods, are recognized in the development of scald r 
each bearing a different relation to remedial measures. 
