746 THE SMALL-MAMMAL PROBLEM 
groups of small mammals, and most probably in favour of 
many other organisms also. An attempt to solve the small- 
mammal problem by purely destructive methods is doomed, 
therefore, to failure; it opens a vista of endless strife with 
the organic world, fraught possibly with great danger from 
unforeseen consequences, infinite expense, and no satisfaction. 
Small mammals in themselves are not evil things; on 
the contrary they play a great part in that complex natural 
mechanism by which all animals and plants are brought into 
relation with each other; a mechanism in which every living 
thing has to do its exact share of the work of keeping the 
face of the earth variegated and happy. Aware of this fact, 
and of the complexity of the relations subsisting between 
each and all species, it becomes impossible to assert with 
confidence that we can afford to dispense entirely with any 
single species now forming part of the British fauna. It 
is only when man, disturbing the Balance of Nature for his 
own ends, unduly favours one species or group of species, 
that evil results from small mammals. ‘Noxious species” 
have become ‘‘noxious” in consequence of our own careless- 
ness and stupidity ; to eliminate them, and to remain careless 
and stupid, is merely to invite other species, at present 
innocent, to stray and become ‘“‘noxious” in turn. 
Considerations of health and economy forbid all thought of 
leaving the small-mammal problem unsolved. Simple destructive 
methods alone, as shown above, will not solve it. To devise 
adequate preventive methods seems therefore to be the only 
course now left open !to us; in such methods alone can we 
hope to find a real solution to the problem. The most 
serious objection to preventive methods is their cost. To 
put in practice a vast scheme of rat and mouse proofing will 
cost an immense sum of money, and it will tax the national 
energy and resources for many years. A cheap remedy for 
ills springing from the negligence of two thousand years is, 
however, more than we can reasonably expect. Every 
farthing spent on prevention will produce permanent benefit ; 
while sums spent upon mere destruction of rats and mice 
can procure no more than temporary relief. 
The preventive methods contemplated are of two kinds. 
