And the most perfect machine is that which transmits the engendered force, with the least possible waste or abandonment, to its point of ultimate expenditure in work. All these hypothetical correlates of force, therefore, predicated upon the doctrine of force-transmutation, have no foundation in fact, since the force transmitted from the point of generation to the point of expenditure undergoes no change but that of direction, in its passage along rope, wire, belt, pulley, shafting, etc. A man whose limbs have been paralyzed, may still will to remove mountains. The will-power is the same, but the mechanical contrivances for its transmission are wanting. Of the actual point or centre of this force-generation, in the case of the will-power, we know nothing; but the moment the power is started on its way towards the point of force-expenditure, whether it traverses the nerves and tissues of the brain, or the right arm or the left, or a crowbar or pickaxe, it is in no sense distinguishable from the force that traverses a rope and pulley. Nor is there any evidence that it undergoes molecular changes, or becomes modified or conditioned by any nearly or remotely related force, as it darts along the nerves, runs through the contracted tissues, electrifies the crowbar, or flashes into work from the point of a pickaxe. Whatever produces, or tends to produce, motion, or an alteration in its direction, is mechanical force, no matter from what force-centre it may start. When we can definitely determine the centre of vital force, as exercised in building up vital structure, _not in wielding pickaxes_, it is to be hoped we shall be able to distinguish, by the proper correlates, vital force from that which is mechanical. But the task is manifestly a hopeless one with the materialists. Professor Beale positively denies that there are any such physical force-relations as those claimed by the materialists, and asserts that vital force bears no relation, or correlation, to either chemical or physical force; that the one is a distinct and separate factor from the other, and cannot be interpreted in the same force-formulæ. He says: "The idea of motion, or heat, or light, or electricity _forming_ or _building_ up, or _constructing_ any texture capable of fulfilling a definite purpose, seems absurd, and opposed to all that is known, and yet is the notion continually forced upon us, that vitality, which does construct, is but a correlate of ordinary energy or motion."