The individual would then be represented thus [J]--unlike the bird, his _point d' appui_ would be solid, and his arms would be far more unyielding than feathers. Yet not one athlete in a million could spring upwards, so as to stand upon the summit of the U. Man's "pectoral muscles"--as physiologists call the mass of flesh below the collar bone and above the nipple--are intended to move the arm; the bird's pectoral muscles are intended to move the body. Cut off a man's arms and pectorals--the counterpart of the bird's wings and fleshy breast--and he has barely lost a tenth part of his weight; on the other hand, cut off the corresponding parts of a bird, i.e.t the pinions and the muscles which move them, and not a tenth part of the original weight is left behind. Speaking coarsely, we may then affirm that man's body is relatively about a hundred times heavier--air being the standard--than that of a bird, and his pectoral muscles, relatively to his body, a hundred times less in bulk. Consequently, even if a human being could, by muscular action, develop the bulk of his "pectorals," so that they should be relatively to the rest of his frame, equal to those of a bird, still his bulk would be so much more solid than that of the bird's bones, flesh, and feathers, that his power of flight would be a hundred times less. A man, with the exception of his lungs, is in health, solid or fluid, in every part of him; a bird's bones, on the contrary, are everywhere permeated by air cavities, which make them as light as pith or cotton wool. A pound of lead and a pound of feathers are certainly equal in weight, yet, if both are allowed to drop from a balloon, the first will reach the ground a long time before the second. In like manner, by contrivance, I could with my breath sustain an ounce of eiderdown in the air, although I am quite powerless to sustain, by like means, the same quantity of solid meat. I say nothing of the relative position of the shoulder-joint in man and birds--although the point is physiologically important. Again, we may assert that the originators of the angelic mythology were absolutely ignorant of that which is called comparative anatomy. We have already expressed our belief that no one has a right to expect that people will believe in the reality of a man's knowledge respecting the unseen world, so long as he is palpably at fault in his notions respecting the visible creation. Consequently we assert that one who is careless as regards actual phenomena and ignorant of common truths, cannot be trusted in metaphorical, mythological, or divine lore.