If men have the faculty of living under all climates, they make use of that faculty, as we know, with extreme reserve. They have never permanently inhabited the polar regions and the perpetually snowy summits of the mountains: it is only at intervals that a few pioneers have temporarily ventured thither. Starting from this fact, it was long believed that the zone of eternal snows was not inhabited by any living being. Even men of science admitted, as an article of faith, that where man could not fix his residence no animal could live. They made, however, a concession with respect to vegetables, and particularly as regarded the lichens and the mosses. Well, observation and research conjointly, have erased this article of faith from the scientific code. It has been demonstrated that the icy regions, which man visits only at rare intervals, and where he sojourns but for a time, are the home of a certain number of animal species, more or less allied to the human species. The scientific exploration of these regions dates only from our own time. Spitzbergen, and the summit of the Alps,--such are our points of comparison. It is difficult to conceive of anything more interesting than the historical exposition of the limited _Fauna glacialis_. First, let us take the discovery, comparatively recent, of a small rodent of the mouse order. THE ARVICOLA LEUCURUS, OR ARCTIC VOLE. On the 8th of January 1832, a Swiss naturalist, M. Hugi, started from Soleure to study the winter condition of the classic glacier of Grindelwald. The undertaking was in many respects a difficult one; the sides of the Mettenberg, bordering on this glacier, were covered with an uniform stratum of hardened snow; a pathway had to be cut out with the pickaxe. M. Hugi and his companions did not arrive at the Stierreg until towards evening. [Illustration: FIG. 9.--Among the Alps.] A goatherd lives there during the summer. They sought around and about for his little cabin, but, on the uniform white carpet of snow which covered everything, no sign of it could be detected. At length they came upon a little mound, which they immediately proceeded to excavate; and late in the night they discovered the roof of the hut. They then redoubled their efforts to sweep away the snow obstructing the door. On opening it a score of mice emerged from the cabin, some of which they killed. For a picture of the poor victims we are indebted to M. Hugi. "These little rodents are of a yellowish gray, and very slender; from the head to the tip of the tail they measure about nine inches. The hind paws are of a length wholly disproportionate to the fore paws. The tail and ears are naked; their transparency is remarkable.... This animal," adds M. Hugi, "appeared to me completely unknown, and I do not remember to have seen it in any zoological collection." After determining its genus and species, the intrepid explorer of the Alps was entitled to have given it a name; but this honour escaped him.