26 MANUAL OF FRUIT DISEASES 
It has, beyond reasonable doubt, been demonstrated by means 
of the X-rays that the disease develops internally before there 
are any external signs of it. The first outward symptom of the 
disease is the appearance of slightly sunken spots here and 
there over the surface, usually most numerous toward the blos- 
som-end (Fig. 7). These spots or pits tend to a circular form 
and vary from mere dots to depressions measuring a quarter of 
an inch or more in diameter. They look like hail or sand 
bruises (Fig. 7). On a red variety the color is at first darker 
red, while on a green variety the spots are darker green. Finally 
the depressed areas are brown. As the fruits mature the pits 
become more numerous and deeper, but the skin covering them 
is not broken nor ruptured in any way. Another form of the 
disease is found in what is known in the western United States 
as hollow-apple. This form is sometimes called confluent 
bitter-pit or crinkle because the upper surface of the fruit 
develops rough folds giving it a crinkled appearance. 
If an affected apple is cut open, an area of the flesh directly 
beneath a pit is found to be dead, brown, dry and spongy, or 
corky. On account of these characters various names have 
arisen: dry-rot, apple brown-spot, leige (cork disease), and 
others. Throughout the pulp of the apple there are usually 
found brown streaks or spots of dry, spongy flesh which do not 
extend to the surface of the apple, and which are not connected 
with the surface lesions. Where the pits and internal brown 
spots are numerous the apple may have a bitter taste, whence 
the name bitter-pit. 
There are many appearances similar to, or mistaken for, 
bitter-pit. The apple is subject to several fruit-spot diseases 
some of which may be regarded as identical with stippen by 
the casual observer. The New England fruit-spot is distin- 
guished from stippen by its spots being decidedly less 
sunken, and by the lack of semblance to a bruise. In the 
fruit-spot one or more black pimples develop on the affected 
