PRESIDENTIAL ADDRESS. 163 
Any fence system requires, however, constant and minute 
supervision. A single act of carelessness, as, for instance, 
leaving a bag hanging over a fence or a pole connecting the 
stack side with the outside, may lead to a considerable in- 
festation of a clean stack, with all that this entails. 
Considering the efficiency of fences for wheat stacks, 
destruction of the mice by poisoning, as with strychnine 
or phosphorus, does not commend itself in this connection. 
There is, in addition, the remote possibility of poisoned 
grain or bait getting mixed with the good grain, whilst the 
presence of abundant food would lessen the likelihood of 
the poison being taken. Doubtless systematic poisoning, 
combined with domestic and barrel traps, may tend to keep 
down the numbers of mice in farm-houses and outbuild- 
ines. I do not see that it is practicable to control the mice 
in fields when they are feeding on much shed grain. 
The deliberate spread of the organisms of disease amongst 
the mice does not seem capable of achieving much. The 
only form of ringworm of an aggressive type that I have 
seen amongst them is favus. Mice so affected have come 
from divers localities, but the disease, in spite of such an 
extensive distribution, does not seem to have done much 
in checking the pest. Doubtless those affected eventually 
die from interference with sight and obstruction to the 
nose. How long this takes I am not aware, but some seem 
to think the condition progresses rapidly. If the disease 
were quickly communicable, one would expect to find many 
more mice affected than is the case. Laboratory cultures 
do not seem to produce lesions rapidly. The organisms 
could only be distributed effectively throughout the mouse 
population by inoculating large numbers of mice, firmly 
establishing the disease, and then setting them free. This 
would be laborious and expensive, whilst seed mice would 
have to be caught in numbers for purposes of propagation. 
