The most ancient forms of measurement have, therefore, been taken from the length of the several subdivisions of the hand. The capability of the hand of assuming the hollow shape of a spoon, and of being stretched like a shovel, determines its use for gathering and for turning up matter. The curvature of the fingers forms a strong and broad hook, which renders excellent service in climbing; and the thumb, whose position enables it to be placed opposite all the other fingers, acts in conjunction with the latter like a pair of pincers, capable of seizing and feeling smaller objects. The thumb being easily moveable and strong at the same time, is a privilege of the human hand. It powerfully opposes itself against the other fingers into the _fist_, for the seizing and holding of heavy objects. In doing this the thumb indeed performs almost as much as the remaining fingers taken together; it represents one half of a pair of pincers, wherefore _Albin_ has called it _Manus parva_. The unequal length of the fingers is well adapted for the taking hold of spherical forms, and the fingers being bent towards the hollow of the hand and held together, encloses an empty space, which is shut by the thumb serving as a lid. The wrist of the hand, having a circular shape, and being composed of several bones, is much less exposed to the danger of being broken, than if one single curved bone were to take its place. Its cavity, which by _strong transversal ligaments_ is transformed into a ring, protects the bending tendons of the fingers from pressure and friction. The firm connection between the middle hand and the wrist renders possible the actions of _stemming_ and _hurling_ with the hands, and the longitudinal curve of the separate bones of the middle hand, as well as their lying one at the side of the other, and convexly towards the back of the hand, facilitates the forming of the cavity of the hand. The great moveability of the fingers, and the many possible combinations of their relative positions, have made them the instruments of language by signs. The deep slits separating them allow of folding the hands, in order to press with double force, and the bending of the two last finger-joints, which can only take place at an angle, imparts to the clenched fist a force which once usurped the place of right. How necessary the joint action of both hands is for certain performances is proved by the old proverb: _Manus manum lavat_. In short, all the thousandfold occupations of the hand which necessity commands and the mind develops, and which are an exclusive prerogative of man, become practicable through the wonderful structure of this instrument.[1] As regards the system of the gymnastic training of the fingers in particular, which I am now placing before the public, it is founded on an important fact, namely, the action of the LIGAMENTS AND TENDONS.