Fusarium Blight of the Soy Bean 
19 
other disinfectants were employed with much less success. After 
washing off the acid in three or four changes of sterile water, the 
seeds were transferred into sterilized moist chambers in the bot- 
toms of which several layers of moist filter paper had been placed. 
Germinated seeds on which there was no evidence of contamina- 
tion after a day or two were transferred to sterile test tnbes^ the 
bottom of each of which contained a wad of moistened filter 
paper.^ If, during germination or transfer, contamination occurs, 
it generalh^ becomes evident on the seedlings or white paper, 
especially if the seedlings are set aside until they have grown to 
a height of 3 or 4 inches.^ 
More recently, however, such precaution to maintain virulence 
was found to be unnecessary because the age of cultures seemed 
to have little effect upon their virulence. Old cultures gave as 
high a percentage of infection, if grown on proper media and 
transferred frequently, as they did when first isolated. 
METHODS OF STUDY AND PRESENTATION 
All transfers of different strains in a set for comparison were 
made to a certain medium on the same day and to additional 
media to proAude the necessary cultural characters. Adien species 
were compared, they were always of the same age and were grown 
on the same medium. As many comparisons could be made on 
the same day as there were species and kinds of media in the set. 
If sufficient data had not been obtained, if certain cultures were 
abnormal, or if other species or media Avere to be used, new sets 
were prepared of all of the species using the desired media and 
comparisons were again made thruout the series. 
Cultural differences also arise as a result of the emplo3unent 
of spores or a bit of mycelium in inoculation. In the former case 
the young cultures quickly produce spores with a scant mycelial 
groAAdh, Avhile in the latter the mycelial groAvth is abundant and 
there is a paucity of spores. For this reason spores from sporo- 
dochia, Avhen present, were used, and in all cases, in so far as was 
possible, the same kind of inoculum was transferred for all cul- 
tures of a set. When the production of spores becomes subnormal, 
as it often does in cultures, considerable time and patience may be 
required to bring the strain back to a “Xormkultur.” This Avas 
^For making this last transfer, dip the ends of long tweezers into 95 per cent alcohol 
and ignite in the flame. This sterilizes instruments, burns off the excess of alcohol, 
and leaves them dry and cool enough for immediate use. 
^The use of agar as a substratum for this purpose (Carman and Didlake, 9), and 
Sphagnum moss, did not prove to be satisfactory. Soil, too, has a disadvantage in that 
it does not show the contaminations as readily as filter paper or agar. 
^An oat sprouter with glass front, heated by a kerosene lamp and costing about 
$10, makes a good light incubator for such purposes when the greenhouse is not con- 
veniently located or the temperature suitable. This sprouter is unsuited, of course, to 
cultures or material requiring a constant temperature. 
