158 ZOOLOGICAL GARDENS. 
in their modes of life are the natural results of the 
circumstances in which the animals are respectively 
placed ; and that the habits of each, in a situation 
favourable to the change, undergo a thorough revolu- 
tion. Place the means within his reach, and the con- 
structive instinct of the solitary Beaver becomes fully 
developed : withdraw those means, and the once skilful 
builder degenerates into a burrowing hermit. Those of 
Europe are for the most part met with in the latter 
predicament, the neighbourhood of civilized man having 
thinned their numbers and rendered their associations 
perilous. In America, on the contrary, they form popu- 
lous villages ; but only in the back and unsettled parts 
of the country : those which are found on the confines 
of the different settlements have precisely the same 
habits with the European animals. 
That similar villages formerly existed in various parts 
of Europe, and more especially in the north, we have 
abundant proofs in the ruins of these ancient edifices. 
But it seems to have been too hastily taken for granted 
that none such are to be found at the present day. In 
the Transactions of the Berlin Natural History Society 
for 1829, an extremely interesting account is given by 
M. de Meyerinck of a colony of Beavers, which has 
been settled for upwards of a century on a little river 
called the Nuthe, about half a league above its conflu- 
ence with the Elbe, in a desert and sequestered canton 
of the district of Magdeburg. Our author speaks of 
this little settlement as consisting, in the year 1822, of 
no more than from fifteen to twenty individuals : but 
few as they were they executed all the laborious tasks 
of a much more extensive society. They formed them- 
selves burrows of thirty or forty paces in length, on a 
level with the stream, with one opening below the 
surface of the water, and another upon the land ; built 
