Ve'rmin of the Farm. 
215 
But although the gradual extermination of the black rat 
has been attributed to the antagonism of the two species, and 
to the superior strength of the brown rat, several instances have 
been noted in which the two species have been found living 
together within a very circumscribed area, as, for example, on 
board the same ship.' 
The account given of the black rat in Bell’s “ British Quad- 
rupeds ” is not satisfactory, the information as to its present dis- 
tribution in this country being very meagre, and little or nothing 
being said as to its geographical range beyond the British Isles. 
The present writer has endeavoured to supply this deficiency in 
the essay referred to. 
As to the existence of a third form of rat in the British 
Islands, the so-called Mus hihernicus, the reader may be referred 
to the Zoologist, 1889, p. 321 (where a figure is given), 1890, 
p. 135, and 1891, pp. 1-9. 
On most farms at the present time there are more rats than 
poultry, and the rats begin to increase earlier than do the 
ducks or fowls. They should therefore be dealt with accord- 
ingly. An open winter causes the fields to be more than 
usually full of rats. After vegetation has commenced and 
when birds have begun to lay, it is difficult to hunt the hedge- 
rows properly. The banks and holes should be ferreted in good 
time. When cats, weasels, and stoats were more numerous, and 
hawks and owls were less molested, rats and mice had these 
natural enemies to reduce their numbers, but now it is otherwise ; 
and with corn stacked about the land, and with sheep trough- 
fed with com and cake in all directions, rats find plenty to eat, 
and increase in proportion. 
Concerted action on the part of farmers whose lands adjoin 
might be easily arranged, and would be generally beneficial. If 
one man sets to work with his ferrets, poison, or traps to reduce 
the stock of rats on his farm, the likeliest holes and banks are 
quickly re-tenanted by the excess of rats upon some neigh- 
bouring farm, where the younger are persecuted by the older. 
Eats emigrate from one farm to another, as convenience 
suggests. If only one occupier, here and there, goes to work 
to have a day’s slaughter among the vermin, the stock of rats 
in the country rapidly readjusts itself to new conditions, just as 
water finds its level ; and, before the time for breeding begins, 
the surplus breeders of one place will take possession of any 
vacant quarters which may be found on another. 
As regards rats and mice, then, we would advise (1) in the 
• Halting, Essays on Sj)ort and Natural History, 1883, pp. 164, 165. 
