INCREASE AND DECREASE OF ANIMALS 101 



l societies in holes under some sheltered ditch-bank. 

 An old one, which I weighed, was only one dram and 

 five grains in weight. 



Mankind appear to be progressively increasing. It 

 was an original command of his Creator, and the animals 

 domesticated by him, and fostered for his use, are 

 probably multiplied in proportion to his requirements ; 

 but we have no reason to suppose that this annual aug- 

 mentation proceeds in a proportionate degree with the 

 wild creatures upon the surface of the globe ; and we 

 know that many of them are yearly decreasing, and 

 very many that once existed have even become extinct. 

 That there are years of increase and decrease ordained 

 for all the inferior orders of creation, common observa- 

 tion makes manifest. In the years 1819 and 1820, all 

 the country about us was overrun with mice ; they har- 

 bored under the hassocks of our coarse grasses ,(aira 

 caespitosa), perforated the banks of ditches, occasioned 

 much damage by burrowing into our potato heaps, and 

 coursed in our gardens from bed to bed even during 

 daylight. The species were the short-tailed meadow- 

 mouse, and the long-tailed garden mouse, and both 

 kinds united in the spring to destroy our early-sown 

 pease and beans. In the ensuing summer, however, 

 they became so greatly reduced, that few were to be 

 seen, and we have not had any thing like such an in- 

 crease since that period. It is probable that some dis- 

 ease afflicted them, and that they perished in their holes, 

 for we never found their bodies, and any emigration of 

 such large companies would certainly have been ob- 

 served ; yet the appearance and disappearance of crea- 

 tures of this kind leads us to conclude that they do oc- 

 casionally change their habitations. 



A large stagnant piece of water in an inland county, 

 with which I was intimately acquainted, and which I 

 very frequently visited for many years of my life, was 

 one summer suddenly infested with an astonishing 

 number of the short-tailed water rat, none of which had 

 previously existed there. Its vegetation was the com- 

 mon products of such places, excepting that the larger 

 portion of it was densely covered with its usual crop, 

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