As we have found in the case of shampooing, a great deal of the suffering of any part can be taken out by giving it something else to do. A portion of the good done by rubbing an aching leg is no doubt accomplished by setting the nerve at work upon the sensations of pressure and of heat and so diverting it from that of pain, but another portion is probably due to the fact of motions producing changes, in the nature of mechanical and chemical decompositions, in the substance of the tissue; thus by a well known physiological law summoning a concentration of the nervous forces to the particular part. Nature is thus accelerated in her action there, and as that action is always toward cure (so long as life and hope exist), the nerves of the part are reinforced to act sanely. To be weak is to be miserable--to be strong is to be free from pain--thus the nerve's returning vigor eliminates its suffering. The fresh blood that is pumped into the part by motion brings about another set of ameliorating changes of more especial importance where the pain is caused by a local lesion instead of rather being sympathetic with the whole systematic debility. Whatever be our theory, the tenet that motion relieves pain, as a tenet, is as old as the "_back- straightening_" process used in some shires by the British turnip-hoers who on coming to the end of their rows lie down and let the rest of the women in the field walk over their toil-bent spine and cramped dorsal muscles, while as a fact it is as old as pain itself. On Lord's Island, therefore, we have a room fitted up with apparatus intended to give passive exercise to every part of the body which the pain of abandoning opium is especially likely to attack.