21 



The cork and tubes beinpr adjusted, the apparatus was ready for action. A 

 spirit-lamp applied to the flask liberated a stream of chlorine, a gas which, if 

 breathed, except when diluted with many times its bulk of air, is absolutely 

 irrespirable. All the rat's holes havinti; been covered over, one after another 

 was opened, the India-rubber tul)e introduced, and a stream of chlorine 

 directed down each. The space between the floor and ceiling must have been 

 filled with a mixture of chlorine and air that no animal could have breathed 

 and lived. Since that time I have seen no rats. Old and young have alike 

 disappeared. Should a stray adventurer make his appearance, I shall repeat 

 my inexpensive remedy, and am now congratulating myself on having, for the 

 present at least, extirpated the enemy." 



Included in the Mttridfc, and constituting a very large sub- 

 family, are the Arvicolince, the field-mice, and in many locali- 

 ties their depredations have established them as serious pests. 

 In the Massachusetts Agricultural Report for 1861 I gave a 

 full account of their haliits, and also in the United States Agri- 

 cultural Report for 1863, to which I would refer for interesting 

 facts concerning them. The field-mice are particularly injuri- 

 ous to plantations of young fruit-trees in winter, gnawing the 

 bark off the stems at the height of the snow, leaving a wound 

 which sometimes completely encircles the wood, which of course 

 is fatal to the life of the tree. They are also destructive in the 

 grain-fields, and in granaries, and when introduced, in hay, 

 from the field into the barn, are very mischievous, gnawing the 

 fodder and cutting it into fragments, and impregnating the 

 whole mow with their peculiar odor. There are several spe- 

 cies of field-mice in this State, included in different genera, 

 the most mischievous of which are the short-tailed field-mice 

 Arvicola. These animals are easily recognized by their short, 

 thick body ; short tail, usually less than half the length of the 

 body ; and short, strong limbs. All the species of this group 

 burrow in the earth, or beneath the roots of a shrub or tussock 

 of grass. Tiiey all feed upon grasses, bulbous roots, seeds and 

 grain ; they do not hibernate, but are active through the win- 

 ter, seeking their food through the deepest snows. 



These short-tailed field-mice can hardly be seen without being 

 recognized, their peculiar form and habits giving them charac- 

 teristics not to be confounded with any other animals, except, 

 perhaps, the shrew-moles, which have forms somewhat similar 

 to those of the mice, but they have more diminutive eyes ; their 

 ears are hidden in the adjacent fur, and their heads are. thinner 

 and more pointed. Care should be taken in destroying the 

 mice not to include in the general slaughter these shrews, for 

 they, with the moles, are eminently beneficial, their food con- 

 sisting of insects and larvae. If the teeth of both shrews and 

 moles be examined they will prove that vegetable food could 

 not form part of the animals' diet, for they are very small and 

 fine, and the strong, sharp, chisel-shaped incisors which all the 



