150 J. B. OLELAND. 
mice by fumigation with carbon bisulphide, which were 
successful as far as they went, but which made little im- 
pression on the multitudes present, Mr. England hit on his 
double-fenece device, with the results mentioned above, in 
the following way. One night, when walking round the 
stacks of wheat near the railway lines, the sleepers and the 
track being covered with mice, he noticed that the animals 
could be driven ahead between the rails for a fairly long 
distance before scattering. This observation, combined with 
the fact that he had noticed that the mice not only came 
into the stack from outside to feed, but also went out from 
the stack for water and to play, suggested the idea of sur- 
rounding the stacks with a double fence, access to the space 
between the two fences being rendered easy for the mice 
inside the stack and for those outside the fences, but egress 
from the space impossible in either direction. The mice, 
once inside the outer space, were then periodically driven 
into pits in the corners, and killed with carbon bisulphide. 
Mr. England lays considerable stress on the value to his 
scheme of the habit the mice have of leaving the stacks 
at night to play. He says: ‘‘I have watched the mice 
chasing each other for hours after they have been feeding, 
the liveliest time for playing being about 3 a.m. One night I 
put a tin dise (like a rat-stop on a ship’s rope) on one of 
these poles, and in ten minutes the pole was lined with mice, 
those above the stop looking down, and vice versa, all wait- 
ing for those in front to move on. When I came up close 
with my lantern the two armies ran back opposite ways. 
This was the strongest proof of my theory that the mice 
were going in and out of the stacks all night. My double 
fence therefore catches them when they attempt to cross 
the trapping zone.’’ 
Talking of the disappearance of the mice, and other in- 
teresting points, Mr. England goes on to say: ‘‘The cold 
weather seemed to stop further multiplication; though, 
