For a considerable period only a single species was known--the marmot properly so called (_Arctomys marmotta_, Gmelin); but four others must now be added:--1st, The marmot of the Caucasus (_Arctomys musicus_), still imperfectly known; 2d, The marmot of Canada (_Arctomys empetra_), who clambers up the trees like a cat, and is distributed throughout all North America, particularly in Hudson's Bay, and Alaska, on the north-west coast; 3d, The _Arctomys monax_, who appears to be peculiar to Maryland; 4th, The Russian marmot (_Arctomys citillus_), of the size of a field-mouse, and of a brown colour, spotted with white; 5th, The marmot of Siberia (_Arctomys bobac_), smaller than the common species, of a yellow gray, and building vast burrows shaped like a funnel. Will the reader permit us an allusion, in passing, to a question which we do not see discussed in books of natural history? Formerly among the treasures of ancient druggists figured a kind of panacea, called "Graetz's balls." What were these "Graetz's balls," at one time esteemed as a universal medicine, but no longer included in our pharmacopeia? This was their origin:--The subterranean dwellings which certain species of marmots construct with so much skill, are each composed of two galleries, which unite together like the arms of a Y, and terminate in a _cul-de-sac_. There are found the globules of clay known as "Graetz's balls." They are an industrial product of our rodents, as M. Oscar Schmidt established in 1866, by close observation of the _Arctomys bobac_ of the Zoological Garden of Vienna. The marmot creates these balls by scratching up the earth, and appears to amuse himself--a child's amusement!--by rolling them to and fro in his galleries. THE CHAMOIS. "Even so This way the chamois leapt."[21] Must we omit this graceful ruminant from the number of mammals inhabiting the eternal snows? No; for it is not of his own will that the chamois has taken refuge upon the snowy peaks of the Alps. If we meet with him there, it is because he seeks to shelter himself from the destructive instincts of man.