MIGRATION OF RATS. 



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 increase since that 

 period. It is probable that some disease 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 

 observed ; yet the appearance and disappearance of 

 creatures of this kind leads us to conclude that 

 they do occasionally 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 common products of such places, 

 excepting that the larger portion of it was densely 

 covered with its usual crop, the smooth horsetail 

 (equisetum limosum). This constituted the food 

 of the creatures, and the noise made by their champ- 

 ing it we could distinctly hear in the evening at 

 many yards' distance. They were shot by dozens 

 daily ; yet the survivors seemed quite regardless of 

 the noise, the smoke, the deaths, around them. Be- 

 fore the winter, this great herd disappeared, and 

 so entirely evacuated the place, that a few years 



