The physiognomy of the hand stands close to that of the face in significance and is in some relations of even greater importance, because the expression of the hand permits of no, or very slight, simulation. A hand may be rendered finer or coarser, may be rendered light or dark, the nails may be cared for or allowed to develop into claws. The appearance of the hand may be altered, but not its physiognomy or character. Whoever creases his face in the same way for a thousand times finally retains the creases and receives from them a determinate expression even if this does not reveal his inner state; but whoever does the same thing a thousand times with his hand does not thereby impress on it a means of identification. The frequent Tartuffian rolling of the eyes finally gives the face a pious or at least pietistic expression, but fold your hands in daily prayer for years and nobody would discover it from them. It seems, however, of little use to know that human hands can not be disguised, if they are little or not at all differentiated; but as it happens they are, next to the face, the most extremely and profoundly differentiated of human organs; and a general law teaches us that different effects are produced by different causes, and that from the former the latter may be inferred. If then we observe the infinite variety of the human hand we have to infer an equally infinite variety of influences, and inasmuch as we cannot trace these influences any further we must conclude that they are to be explained causally by the infinite variety of psychical states. Whoever studies the hand psychologically gains in the course of time a great deal of faith in what the hand tells him. And finally he doubts it only when chirognomy conflicts with physiognomy. If in such cases it is observed that the hand is more likely to be correct than the face, and that inferences from the hand more rarely show themselves to be false, one is reminded of the dictum of Aristotle, “The hand is the organ of organs, the instrument of instruments in the human body.” If this is correct, the favored instrument must be in the closest kind of relation with the psyche of the owner, but if this relation exists there must be an interaction also. If the hand contained merely its physical structure, Newton would never have said, “Other evidence lacking, the thumb would convince me of God’s existence.”