In generals the evidence is clear, and it must, therefore, be true in the minutest particulars; for the law of aggregates is the law of individuals—the mass and the atom have like essential conditions. It is, indeed, difficult to trace facts into the inmost nature of things, and quite impossible to penetrate by observation as deep as principles lead by the process of mental investigation—so much more limited in the discovery of truth, even the truth of physics, are the senses than the reasoning faculties. We need, however, but open our eyes to see that the diversities of form among all created things are, at least, as great as their differences of character and use; and whether there be a determinate relation of appearance to constitution or not, there is at least an unlikeness of configuration or dimension, or of both, wherever there is unlikeness of quality; and that this difference of form thus commensurate with difference of constitution, is not merely a matter of arbitrary distinctiveness among the multifarious objects of creation, as names or marks are sometimes attached to things for certainty of reference and recognition, appears from such facts and considerations as follow— 1. All mineral substances in their fixed, that is, in their crystaline form, are angular with flat sides and straight edges. This is not only a general rule and an approximate statement, but exactly accurate and universal; for in the few instances of crystals occurring with convex or curvilinear faces, such as the diamond, it is known that their primary forms have plane or flat faces and a parallel cleavage—making the rule good against accidental influences and superficial appearances. Here then we have a mode of configuration appropriate to and distinctive of one whole kingdom of nature. 2. In vegetables we have a different figure and characteristic conformation. Their trunks, stems, roots and branches are nearly cylindrical, and uniformly so, in all individuals clearly and completely within the class. Soon as we enter the precincts of life curvature of lines and convexity of surface begin to mark the higher styles of existence, the law being that nothing which lives and grows by the reception and assimilation of food is angular, rectilinear or included within plane surfaces. Inert bodies take straight, but life assumes curve lines. 3. In animal forms the curve or life line is present of necessity, but it undergoes such modification and departure from that which marks vegetable existence as our law demands. We no longer have almost cylindrical simplicity of shape as the sign of character and kind, but, retaining curvity, which is common to vitality of all modes, we find the cylinder shaped or tapered toward the conical, with continually increasing approach to a higher style of configuration as we ascend toward a higher character of function.