Spore-Culture. III 
place the spores in water, and they will germinate at once— 
for example, U. segetum, longissima, etc.; but some require 
a longer period of immersion, eg. T. ¢riticz, which will not 
germinate till after being several days in water. The 
germination of the Tilletia spores can also be conducted in 
a hanging-drop culture in the following manner :—A piece 
of glass tube, about half an inch (12 mm.) in diameter and 
about three-quarters of an iach (18 mm.) long, is cemented 
on an ordinary glass slide, so as to form a deep cell (Fig. 10). 
Fig. 10.—Deep cell for hanging-drop cultures, made by cementing a piece of glass or lead 
tube upon an ordinary glass slide. 
Into this is placed a small quantity of water. The drop 
containing the spores to be germinated is placed on the 
centre of a circular cover-glass, which will fit the top of the 
cell (Fig. 11). If the upper edge of the tube which forms 
Fig. 11.—Hanging-drop culture, seen in section. 
the cell be oiled, no air can get into the culture, and the 
germination can be watched for months, as the hanging- 
drop will not evaporate, because the water placed in the 
bottom of the cell keeps the atmosphere saturated, and 
any loss which it may sustain from evaporation is made 
up from the water at the bottom of the cell. 
There is no need to keep these sealed hanging-drop 
cultures in a moist atmosphere, because the necessary 
