returning to his citizen’s duties—­he begins inventing the most diabolic means for the extermination of the little robbers.  All kinds of rapacious birds and beasts of prey having proved powerless, the last word of science in this warfare is the inoculation of cholera!  The villages of the prairie-dogs in America are one of the loveliest sights.  As far as the eye can embrace the prairie, it sees heaps of earth, and on each of them a prairie-dog stands, engaged in a lively conversation with its neighbours by means of short barkings.  As soon as the approach of man is signalled, all plunge in a moment into their dwellings; all have disappeared as by enchantment.  But if the danger is over, the little creatures soon reappear.  Whole families come out of their galleries and indulge in play.  The young ones scratch one another, they worry one another, and display their gracefulness while standing upright, and in the meantime the old ones keep watch.  They go visiting one another, and the beaten footpaths which connect all their heaps testify to the frequency of the visitations.  In short, the best naturalists have written some of their best pages in describing the associations of the prairie-dogs of America, the marmots of the Old World, and the polar marmots of the Alpine regions.  And yet, I must make, as regards the marmots, the same remark as I have made when speaking of the bees.  They have maintained their fighting instincts, and these instincts reappear in captivity.  But in their big associations, in the face of free Nature, the unsociable instincts have no opportunity to develop, and the general result is peace and harmony.

Even such harsh animals as the rats, which continually fight in our cellars, are sufficiently intelligent not to quarrel when they plunder our larders, but to aid one another in their plundering expeditions and migrations, and even to feed their invalids.  As to the beaver-rats or musk-rats of Canada, they are extremely sociable.  Audubon could not but admire “their peaceful communities, which require only being left in peace to enjoy happiness.”  Like all sociable animals, they are lively and playful, they easily combine with other species, and they have attained a very high degree of intellectual development.  In their villages, always disposed on the shores of lakes and rivers, they take into account the changing level of water; their domeshaped houses, which are built of beaten clay interwoven with reeds, have separate corners for organic refuse, and their halls are well carpeted at winter time; they are warm, and, nevertheless, well ventilated.  As to the beavers, which are endowed, as known, with a most sympathetic character, their astounding dams and villages, in which generations live and die without knowing of any enemies but the otter and man, so wonderfully illustrate what mutual aid can achieve for the security of the species, the development of social habits, and the evolution of intelligence, that they are familiar to all interested in animal life.  Let me only remark that with the beavers, the muskrats, and some other rodents, we already find the feature which will also be distinctive of human communities—­that is, work in common.