192 ANIMAL COMPETITORS 
hasten the end. Experiments with similar or- 
ganisms have been reported successful since in 
Russia and in France; but none of the like at- 
tempts made during the mouse-plague in Ne- 
vada in 1908 had'‘an appreciable effect. 
As Mr. Lantz says: 
‘“‘The destruction of noxious mammals is a more 
complicated problem than that of insect destruction. 
The farmer who fights these higher forms deals 
with instincts and intelligence well adapted to cope 
with his own in the struggle for existence. It is 
not enough that he place poisoned food or traps 
in the way of the creatures he desires to destroy; 
he must make the baits attractive and allay the 
natural suspicion of the animals by ridding traps 
of all suggestion of their real nature. He must 
know the traits of the animals and take advantage 
of any habit that will enable him to circumvent and 
destroy them.”’’ 
Furthermore: 
“In warfare against any rodent pest little per- 
manent good can be accomplished except by codp- 
erative effort. Although it always pays the indi- 
vidual farmer or fruit grower to exterminate pocket- 
gophers from his own lands, yet if he can not se- 
cure codperation of the whole community he must 
constantly guard against a return of the pests and be 
ever ready to renew offensive operations against them. 
