Humboldt has remarked, that among several nations of South America, who wear very little clothing, he never met with a single individual with a natural deformity; and the celebrated Linneus, in his account of his tour through Lapland, enumerates constant exposure to solar light as one of the causes which render a summer’s journey through high northern latitudes so peculiarly healthful and invigorating; whilst the reverse is observed in less favoured regions-- ---- “beyond Tornea’s Lake, And farthest Greenland, to the Pole extreme, Where, failing gradual, Life itself goes out; There Winter holds his unrelenting court. Near the wild Oby live the last of men! There, half-enliven’d by the distant Sun, That rears and ripens man as well as plants-- There human nature wears its lowest form!” We will now enter upon the consideration of another of the grand essentials of vitality. Air-- “Vivit Ætherias vitaleis suscipit auras.” The word ‘atmosphere’ is of Greek origin, and signifies a body of vapour in a spherical form. The rapidity of atmospheric air cannot be explained on any principle but its fluidity; therefore atmospheric air, the permanently elastic fluid which surrounds the earth, although invisible, may be said to be material, and to possess all the common properties of matter; for it occupies space, attracts and is attracted, and consequently has weight. It likewise partakes of the nature of a fluid, for it adapts itself to the form of the vessel in which it is contained, and presses equally in all directions. Its power, when vitiated, as a cause of disease, can only be determined by a scientific examination of its properties, especially as regards its affinities to other things. It should therefore claim the attention of every individual, professional or non-professional, who has the comfort of mankind at heart. “It is scarcely possible,” says Professor Davy, “duly to appreciate, in the vast economy of terrestrial adaptations, the importance of the mechanism by which gases and vapours rapidly permeate each other’s bulks and become equally diffused. The atmosphere which surrounds the globe consists of a mixture of several aeriform fluids in certain fixed proportions, upon the proper maintenance of which, by measure and weight, the welfare of the whole organic creation depends.” One of the principal uses of the atmosphere is to supply animals with a medium for breathing. Breathing is an essential effort of the human system. Its immediate effects are the operation of considerable changes on the blood-- “In the blood is life, which vitality depends on air.”