1. It is well known that the portion of the skin which covers a bone and which is then so pulled away that it covers a fleshy part, can not easily identify the point of stimulation. Such transpositions may be made intentionally in this experiment, but they occur frequently through vigorous twists of the body. When the upper part of the body is drawn backwards, while one is sitting down, a collection of such transpositions occur and it is very hard then to localize a blow or stab. So, too, when an arm is held backward in such a way as to turn the flat of the hand uppermost. It is still more difficult to locate a wound when one part of the body is held by another person and the skin pulled aside. 2. The sensation of wetness is composed of that of cold and easy movement over surface. Hence, when we touch without warning a cold smooth piece of metal, we think that we are touching something wet. But the converse is true for we believe that we are touching something cold and smooth when it is only wet. Hence the numerous mistakes about bleeding after wounds. The wounded man or his companions believe that they have felt blood when they have only felt some smooth metal, or they have really felt blood and have taken it for something smooth and cold. Mistakes about whether there was blood or not have led to frequent confusion. 3. Repetition, and hence summation, intensifies and clarifies the sensation of touch. As a consequence, whenever we want to test anything by touching it we do so repeatedly, drawing the finger up and down and holding the object between the fingers; for the same reason we repeatedly feel objects with pleasant exteriors. We like to move our hands up and down smooth or soft furry surfaces, in order to sense them more clearly, or to make the sensation different because of its duration and continuance. Hence it is important, every time something has to be determined through touch, to ask whether the touch occurred once only or was repeated. The relation is not the same in this case as between a hasty glance and accurate survey, for in touching, essential differences may appear. 4. It is very difficult to determine merely by touch whether a thing is straight or crooked, flat, convex or concave. Weber has shown that a glass plate drawn before the finger in such wise as to be held weakly at first, then more powerfully, then again more powerfully seems to be convex and when the reverse is done, concave. Flatness is given when the distance is kept constant. 5. According to Vierordt,[188] the motion of a point at a constant rate over a sizable piece of skin, e.g., the back of the hand from the wrist to the finger tips, gives, if not looked at, the definite impression of increasing rapidity. In the opposite direction, the definiteness is less but increases with the extent of skin covered. This indicates that mistakes may be made in such wounds as cuts, scratches, etc.