II] Finger and Toe, and Wart Disease 39 
were formed the chances of infecting plants would 
be proportionately diminished and consequently the 
existence of the fungus would be endangered. The 
myxamoebae make their way into the plant through 
the fine hairs near the tips of the rootlets. 
The fungus causing Finger and Toe belongs to a 
group which is very different from the majority of 
fungi. It is not always classified as a fungus, but for 
our purpose may be considered as such. If these spores 
belonged to a fungus similar to those already studied, we 
should expect them to give rise to a number of tube-like 
hyphae known as a mycelium. In this case, however, 
nothing of the kind takes place; when the myxamoeba 
gets inside a root cell it begins to feed on the contents. 
This particular cell seems to make a call on the food 
supplies of the plant and gradually gets larger. The 
myxamoeba continues to feed on the cell protoplasm 
until eventually this is all used up. The large or giant 
cell is thus filled by a naked mass of protoplasm 
derived from the myxamoeba and which is now called a 
“plasmodium.” This is the vegetative portion of 
the Finger and Toe fungus, and so corresponds to the 
mycelium of other fungi. As already mentioned it 
appears as a frothy granular mass. 
The plasmodium is able to pass from the giant cell, 
which it has caused to be formed, into neighbouring 
cells. Here it feeds on the protoplasm and these cells 
gradually enlarge, and eventually become filled by it. 
Examination of a section shows that the giant cells 
touch each other and this is what we should expect 
from the method of infection by creeping from cell to 
cell. Now let us look at the case from the point of 
view of the plant attacked. 
