IO British Uvedinee and Ustilaginee. 
collect specimens which are perfectly mature, if possible, 
upon leaves that are beginning to fade from age, and dry 
them in the ordinary way between blotting-paper. When 
the spring comes, the affected leaves must be soaked for 
twenty-four hours in water, and the spores examined to 
see if any attempt at germination is observable. If not, 
the soaked leaves may be wrapped in an old, well-washed 
piece of calico, and buried for a day or two in the ground ; 
after which treatment, a few spores must be tried in a drop 
of water on a glass slide. Should they fail to evince any 
signs of vitality, the leaves must again be buried for a day 
or two longer, and re-examined. 
The entrance of the germ-tube into the host-plant can 
be observed in various ways. The promycelial spores can 
be applied to the surface of a leaf, and sections made a few 
hours afterwards. This is, however, an exceedingly delicate 
process, and requires not only patience, but considerable 
manipulative skill. A piece of the epidermis may be 
stripped off and laid flat upon a moistened slide, and the 
spores placed on it ; if the preparation be kept in a moist 
atmosphere for a few hours, the germ-tubes can be seen 
boring through the cells. Another plan is to place a mass 
of teleutospores, which has first been seen by the micro- 
scope to be in active germination, on a leaf, and to keep it 
for a few hours under a bell-glass in a moist atmosphere. 
The teleutospore mass can be seen by the naked eye, and 
is a guide to the exact part of the leaf to be examined. 
By a little deft manceuvring, pieces of the epidermis at this 
spot can be ripped off with the point of a penknife, and 
examined either on their external or internal surfaces. By 
similar methods, the entrance of the uredospore and ecidio- 
spore germ-tubes can be observed, only, being larger and 
containing yellow endochrome, the process is less difficult. 
With most of the Ustilaginee, all that is necessary is to 
