WILD ANIMALS IN CAPTIVITY 
resembling that of the well-known beaver. His little 
blunt head and small eyes do not glare like the eyes of 
our crafty foe. 
The largest British species of Armcola must not, how- 
ever, be confounded with its ally A. agrestis, or field vole, 
usually named short-tailed field mouse,” the raids of 
which have, at times, not only caused much annoyance 
and alarm, but have threatened famine in consequence of 
their prodigious numbers, which have destroyed, whole- 
sale, newly-sowed grain, grain in store, trees and shrubs ; 
in fact, all vegetation, green or dried, vanished wherever 
they made their appearance, and this extraordinary in- 
crease of numbers is not always confined to one or two 
species ; several kinds are known whose numbers from 
time to time alarm the inhabitants of the countries they 
visit. It may appear strange, but it is nevertheless true, 
that it is always the smallest creatures in the world that 
are most troublesome, with which it is most difficult to 
deal, and which produce the greatest amount of annoyance 
and suffering. They defy all our attempts to rid ourselves 
of them, and frequently drive us altogetlier out of their 
favourite localities. With all our boasted power we are 
helpless, or nearly so, if we are dealing with the lesser 
kind of mammalia in the form of rats, mice, hamster, 
lemming, etc. (their countless numbers completely over- 
powering all our endeavours to destroy them), not to 
mention the insect tribe in the shape of mosquitoes, tsetse 
flies, ants, wasps, locusts, etc., to say nothing of such 
as require the microscope to prove their existence ; for 
while we can defend ourselves from and kill the larger 
animals whose existence appears in opposition to our 
welfare, we are in far greater danger when opposed by the 
almost invisible or microscopic enemies that are now 
being brought to light by the investigations that have of 
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