36 
POPULAR SCIENCE REVIEW. 
of minute dust. If he has been guilty of brushing in amongst 
the corn, it will still be remembered how his hands and cloth- 
ing became dusted with this powder ; and if at the time he 
should have been clad in sombre black, evidence will have 
been afforded — in the rusty-looking tint of the powder when 
sprinkled upon his black continuations — that, however sooty 
this powder might appear whilst still adhering to the ears of 
corn, it has an evident brown tint when in contact with one's 
clothes. This powder, minute as it is, every granule of it 
constitutes a spore or protospore capable of germination, 
and ultimately, after several intermediate stages, of repro- 
ducing a fungus like the parent of which it formed a part. 
During the growth of the plant its virulent contents flow like 
a poison through the innermost tissues, and at length attack 
the peduncle or axis of the spikelets of the ear, raising np 
the essential organs and reducing them to a rudimentary 
state. Brongniart, who made this species the special subject 
of observation, states that the fleshy mass which is occupied 
by the fungus consists entirely of uniform tissue, presenting 
large almost quadrilateral cavities, separated by walls, com- 
posed of one or two layers of very small cells filled with a 
compact homogeneous mass of very minute granules, perfectly 
spherical and equal, slightly adhering to each other, and at 
first green, afterwards free or simply conglomerate towards 
the centre of each mass, and of a pale rufous hue ; at length 
the cellular walls disappear, the globules become completely 
insulated, and the whole mass is changed into a heap of 
powder, consisting of very regular globules, perfectly alike, 
black, and just like the reproductive bodies of other fungi. A 
scientific botanist of some repute, M. Unger, published a 
work in Vienna during the year 1823, in which he sought to 
prove that this, and allied species of fungi, were not fungi at 
all, but merely broken up cells, or disruptured and altered 
conditions of certain portions of the diseased plants. The 
most satisfactory refutation of this theory may be found in 
the fact that the spores of the smut can be seen to germinate 
under favourable conditions and produce fruit, whereas if 
they were only the ordinary cells of the plant broken up by 
disease, fructification would not take place. 
The spores in this species are exceedingly minute. It has 
been ascertained that forty-nine of them would be contained 
within a space the one-hundred-and-sixty-thousandth part of a 
square inch, hence one square inch of surface would contain little 
less than eight millions. These myriads of spores are shed 
from the ears, and nothing remains but the barren matrix in 
which they were borne when the firmer proceeds to gather in 
his crops. At that time he sees no more of the i( smut," all 
