220 ILLINOIS ACADEMY OF SCIENCE 
METHODS OF CULTURE 
In isolating the fungus from the apples all possible precau- 
tions were taken in order to avoid contaminations. Except 
where otherwise specified the medium used for all cultures was 
cornmeal agar made according to Shears’ formula. 
Before any cultures were made from the tissue of the apples 
the surface, which had been washed in water and dried with 
a clean towel, was wiped with sterilized cotton saturated with 
absolute alcohol. 
THE FUNGUS 
From all but two of the spots Alternaria was isolated. The 
cultures were all alike and originated from the point where 
the needle was put into the agar. From the number of isola- 
tions and the uniformity of the results there would seem to be 
little doubt but that this is the organism which causes the spot, 
although inoculations on healthy apples did not produce the 
same spot. It is probable that in the orchard the fungus gains 
entrance while the fruit is still young, and develops more or 
less with it. In the laboratory no results were obtained with- 
out breaking the skin, and when the inoculations were made 
under the surface a soft rot was produced without any darken- 
ing of the skin of the fruit. 
The Aliernaria found in this spot is not morphologically dif- 
ferent from many other Alternarias which grow on a great 
many hosts. Dr. Elliott, then of this laboratory, now at the 
Arkansas Experiment Station, determined it as Alternaria 
tenuts, variety X. Two other varieties of Alternaria were iso- 
lated by me, one rotting the core of an apple, and one growing 
on the surface of the seed and not rotting the fruit. While 
these are like the Alternaria referred to above, under the mi- 
croscope, and in culture the colonies look the same, they do not 
behave the same when inoculated on fruit. The one char- 
acteristic of this spot produces a rapid rot, the one from the 
core a slower growing rot, and the one from the seed no rot 
at all. Several cultures obtained from Dr. Elliott indistin- 
guishable from these, produced no rot on the apple. One, 
however, caused a spot not unlike the one above described. It 
developed very slowly and make the skin dark, hard, and 
sunken. This was A. fasciculata, a variety of A. tenuis. 
