MILDEW AND BRAND. 
191 
end by mutual pressure. When the outer membrane was 
dissolved or ruptured, these cells escaped, and became detached 
from each other. The cells, thus set free, exhibited a brownish 
or yellow ring around a paler area, in the interior of which an 
inner cell was visible, sometimes globular, often irregular 
in shape. The examination of the ring was not entirely satis- 
factory ; it appeared to be sometimes marked with concentric 
lines having the appearance of wrinkles. The inner - cell had 
granular contents and a central nucleus. When perfectly free 
they were spherical in form, with a distinct membrane of their 
own ; and colourless, except when acted upon by re-agents. 
The means employed to determine the existence of these cells, 
was to soak the spores in muriatic acid, then upon pressure of 
the glass cover, the outer membrane and ringed cells were 
ruptured and the inner cell escaped (fig. 14). 
Germination may be induced in these spores by keeping 
them in a moist atmosphere (fig. 15) ; but the mode does not 
differ from that described above as occurring in the “ corn 
mildew.” Mr. Currey writes : — “ I know no microscopical 
object of greater beauty than a number of fruits of Phrag- 
midium in active germination.” By Phragmidium he means 
the Aregma of this paper, of which Phragmidium is a synonym. 
Well may the reader remark on arriving thus far, “Does 
all this examination and detail refer to the fruit borne in the 
little blackish spots on bramble leaves, which I have hitherto 
overlooked?” Ay, and to several similar spots on other 
plants. Examine carefully the raspberry leaves in your garden, 
and you will probably find similar, but smaller, pustules also 
on the under surface. We sa y probably, because none of our 
British species seem to be equally uncommon with this. 
During the past year we examined hundreds of plants, and 
did not find a single pustule. Such a fate will not await 
you if you should proceed in the autumn to some chalky 
district where the burnet is common. Go, for instance, to 
Greenhithe or Northfleet, on the North Kent Bailway, in 
August or September, where the burnet is plentiful, and the 
leaves will present the appearance of having been peppered 
beneath, from the number of minute pustules of the burnet 
brand scattered over the under surface (fig. 2, upper leaflets). 
Or if you prefer collecting nearer home, visit some neigh- 
bouring garden, if your own does not contain many roses, and 
the leaves will be found equally prolific in an allied species 
(fig. 8) . Should gardens and roses be alike unattainable, any 
bank or wood will furnish the barren strawberry ( Potentilla 
fragariastrum) , and during the latter part of the summer, or 
in autumn, another species of Aregma will not be uncommon; 
also on the under surface of the leaves (fig. 5). All these 
