DoRAN: ON THE GERMINATION OF FUNGOUS SPORES 315 
the germination of which is to be studied should be of the same 
age. The germination of spores from a second culture transferred 
from the first should not be compared with the germination of 
spores from the first culture. 
Distilled water was the medium in which the spores were 
placed to germinate. As is subsequently described more in 
detail, it was soon evident that the distilled water contained an 
insufficient amount of air for spore germination. Consequently, 
the distilled water was in all cases aerated before being used. 
The aeration was accomplished by drawing air through the 
water for about thirty minutes by means of an aspirator and an 
Allihn gas washing bottle. 
On culture plate benches in moist chambers were placed 
glass slides and on them drops of water either containing spores 
in suspension or the spores were shaken off into the drops. It 
is important that all drops of water be approximately equal in 
size especially when the toxic action of fungicides is to be 
tested. Clark (2) studied spore fermination in hanging cultures. 
Duggar (3) used that method also and a modification of it, 
placing the cells in small Petri dishes. Mains (4) germinated 
fungous spores in hanging drops on the cover of a Petri dish. 
When the cardinal temperatures for the germination of the 
spores being studied was unknown, the first step consisted in 
the determination of the optimum temperature for germination, 
and in all later tests the spores were germinated at their optimum 
temperature. Constant temperatures were secured by the use 
of a DeKhotinsky electric oven and a Hearson incubator. 
The next point determined was the minimum length of time 
in which all the viable spores of each fungus will germi ate 
at the optimum temperature. At least six hours more than this 
minimum time period was allowed to elapse before removing 
the slides from the moist chambers aid determining the relative 
number of spores germinated. If slightly less than sufficient 
time is allowed a narrower range of optimum temperatures 
will be found than if more time is allowed, resulting, when the 
results are plotted, in a temperature-germination curve more 
acute than flat at itssummit. If too long a time passes before 
the germinating spores are counted, the germ tubes will have 
grown and branched so as to make counting difficult and un- 
certain. All data are based on relative number of spores germi- 
nating. 
