In the human body all that belongs to the whole inferior creation is represented and reproduced, for man is logically a microcosm, and in his body we find the various orders of natural beings marked by their appropriate modes of construction and configuration—from a hair to a heart, the multifarious parts bring with them the forms native to their respective varieties of being. The bones have in them the material of the mineral kingdom, and they have conformity of figure. In the short, square bones of the wrist, in the teeth, and several other instances, the flatness, straightness and angularity proper to crystalized matter, marks its presence as an element of the structure. The correspondence of the vascular system with the forms proper to vegetation, is most striking. A good drawing of the blood vessels is a complete picture of a tree. Now, animals and vegetables differ widely in their manner of taking in food, but they are alike in the method and end of the distribution of the nutritious fluids, and between them the resemblance of form obtains only in this, as our law requires. There is nothing in trees, shrubs or grasses, that has any outline likeness to the esophagus, stomach or intestinal tube; nothing in them has any resemblance of office, and nothing, therefore, is formed upon their pattern. The roots of trees, which are the avenues of their principal aliment, are merely absorbing and circulating instruments—a sort of counterpart branches in function—and they have, therefore, what scientific people call the arborescent arrangement wherever they find it. If it is answered here that a hydraulic necessity determines the general form of circulating vessels, and that certain immediate mechanical advantages belong to the cylindrical over the square or polygonal shape of tube, our point is not affected. We are showing, now, that the expected conformity never fails. It is essential to our position that mechanical requirements shall not over-rule the general law. The instance given is in accordance, and a presumption rises that even mechanical conformation itself is covered and accommodated by the great principle which we are illustrating. It is enough for us, however, that no facts contradict, though it be doubted whether all the instances cited afford us the expected support.