268 BOTANICAL GAZETTE [NOVEMBER 
Illinois, and were purchased at different times during the year 
1919-20. Each nut was superficially examined and the shell 
carefully removed by cracking it with a hammer. The diseased 
nuts were dropped, shell and all, into suitable sterilized glass dishes, * 
one nut in each dish. A number was assigned to each, but only 
those diseases which were most prevalent and which presented 
the most conspicuous diagnostic features were selected for 
study. 
A preliminary examination was made of thin razor sections of 
diseased tissue mounted in water or xylol, in order to discover 
whether fungi or bacteria were present, and if so, to ascertain 
their general relation to the host tissues. If this examination 
showed any single species of organism to be predominant, isolations 
were made either by direct transfer to cornmeal agar plates, or by 
dilution plating as the case required. These isolations were from 
both exterior and interior portions of the nut, and when from the 
interior were carried out in the following manner. The nut meat 
was cut into with a flamed scalpel and carefully broken apart. 
A central portion of about 4 sq. mm. area was carefully removed 
with a flamed scalpel from one of the newly exposed surfaces, and 
discarded. In the center of the cavity thus made small pieces of 
diseased tissue were loosened with the point of the scalpel, and 
immediately carried in a sterilized loop to the surface of cornmeal 
agar plates. 
Following isolation, the next step was to determine whether 
the fungi isolated were responsible for the various diseased condi- 
tions. Two methods were used; first, pieces of mycelium or a 
few spores were placed on sterile kernels contained in sterilized 
one-inch test tubes;. and second, pieces of mycelium or a few 
spores were placed upon strips of sterile nut meat, 50 uX5 X10 mm., 
which were contained in tubes of sterile water, one strip on the side 
of the tube just above the surface of the water and the other in 
the water. By the first of these methods the rotting power of the 
parasite was made evident within a few weeks by the softening of 
the whole mass. With the second method results were obtained 
more quickly by more or less complete dissolution of the very thin 
sections employed. The following media were used in the case 
of every organism. 
