Spore-Culture. 107 
points, so that when placed under the microscope there 
is no necessity to wipe the lower side of the slide. Of 
course, the length and height of the stand must be propor- 
tionate to the size of the bell-glass. The best form of bell- 
glass is that known by gardeners as a propagating glass, 
which is rather flatter than the ordinary bell-glasses ; the 
advantage being that the slides are not too far above the 
surface of the water in the plate, so that the drops of water 
on them do not evaporate so rapidly. 
Supposing we wish to observe the germination of the 
ecidiospores of Puccinia graminis, having obtained a per- 
fectly fresh-gathered leaf of barberry with the AEcidium on 
it, we proceed as follows. The spores can either be brushed 
upon the slide with a camel-hair pencil, or what will often 
be found more convenient, the zcidium can be gently struck 
upon the dry slide, and a drop of water let. fall upon the 
tiny heap of golden spores that have been displaced. The 
ripe spores will most of them float on the top of the water 
and can be readily observed with a quarter-inch objective. 
The preparation must, of course, not be covered with a 
cover-glass, and it takes a little patience to examine these 
uncovered objects, because the front of the object-glass is 
apt to become'bedewed and misty. The only plan is to 
raise it by the coarse adjustment, wipe it dry, and try again. 
Germination will be well advanced in the course of 
ten or twelve hours, and the migration of the yellow 
endochrome along the germ-tube will by that time have 
taken place. This will be followed by their circumnutatory 
movements and ultimate branching. Earlier examination 
of the preparation will show the germ-tubes emerging from 
the germ-pores, It is useless to attempt to get zcidio- 
spores to germinate unless they are perfectly fresh and 
perfectly ripe. For instance, the spores dug out from the 
bottom of an zcidial cup with a needle will not germinate ; 
