59 
be seen if very highly magnified. If, however, the stalk 
is removed from a not over-ripe mushroom, and the latter 
placed on a sheet of white paper, in the course of a few 
hours so many spores are shed from the gills that a print 
of the gills is produced on the paper. This print consists 
of myriads of spores which have fallen like dust from the 
gills. The spores are the reproductive cells of the fungus 
and, falling to the ground, they grow out to produce tiny 
filaments. They soon begin to absorb water and food 
substances from decaying vegetable matter in the soil and 
manure, and so the vegetable life of the plant is carried 
on. 
Many fungi are much more minute than the mush- 
room, indeed are so small that they can only be pro- 
perly studied under the microscope. As an example of 
such a fungus we have Mucor, the common white mould 
which often appears on damp bread or dung. If a piece 
of bread is kept moist for a few days under a bell-jar 
in a warm place the mould soon appears as a dense 
growth of fungus covering the surface of the bread. Erect 
silky threads stand up from the surface like a miniature 
forest. Microscopic examination shows that the fungus 
consists of two sorts of filaments: fine ones which branch 
and ramify in all directions forming a felt on and in the 
substratum, and the coarser erect ones which stand free. 
The finer network on the substratum is the vegetative part 
of this fungus, while the erect coarser aerial threads are the 
reproductive organs. The individual branching filaments 
are very similar to those described for the mushroom, ex- 
cept that in this case there are no cross walls dividing up 
the tubes. When the aerial filaments have grown for a few 
days there appears at the extreme tip of each a minute 
round swelling like an inflated ball about the size of a pin 
head. The protoplasmic contents of this globular body or 
‘spore-case soon become divided up to form a large number 
of spores, and then it has the appearance of a miniature 
ball full of shot. As the wall of the spore-case becomes 
dry it breaks, scattering its spores into the air as a fine 
dust in all directions; the spores of Mucor and, indeed, 
of many fungi, are very light and easily carried by the 
slightest current of air. When placed in water the spores 
germinate in a few hours, the protoplasm within absorbs 
water, the spore wall bulges in one place and grows out 
forming a fine filament which, given suitable food 
