Afterwards comes the time for exercise of the paralysed limb, for friction, for shampooing, for galvanism; all continued perhaps for months or years with unwearied patience, and I must add with reasonable expectations as to the result. The only additional remark which I have to make is this, that to gain any real good from galvanism, a battery must be procured under the direction of some medical man specially skilled in the use of electricity, and the mode of employing it must be learned thoroughly from him. It is merely idle to purchase a toy machine, and, giving it to the nurse to turn the handle for ten minutes twice a day, to fancy that you are making a serious trial of the effects of galvanism. As a mere money question, a costly machine, and several fees paid in order to be thoroughly instructed in the way to use it, is much cheaper than a cripple child. A few words may not be out of place with reference to cases in which paralysis is mistakenly supposed to exist. Much anxiety is sometimes expressed by parents concerning children who have long passed the usual age without making any attempt to walk; or who having once walked seem to have lost that power. Now it often happens that after any weakening illness a child ceases for some weeks to walk, just as it ceases to talk. The power in both cases was newly acquired, it called for effort which, when strength is regained, will be put forth once more. The same applies to other instances in which children are late in learning to walk; or who, having once walked, leave off walking when a back tooth, or when one of the eye teeth is coming near the surface of the gum, and regaining the power lose it again, or lose at least the desire to exert it more than once during the active progress of teething. But, holding the child under its arms, you have but to put its feet to the ground, and at once it will draw up its legs though it will make no other movement; or take it on your lap and tickle the soles of its feet, and laughing or crying, as the mood takes it, it will move its legs about as freely as you could wish and show that the power is still there, though for the present the child will not take the trouble to exert it. Gradual loss of power over one or other leg, especially if attended with pain either in the back or in the knee or hip, should always call for attention, and induce you to seek at once for medical advice. Such cases generally occur later in childhood than the conditions of which I spoke in the former paragraph, and may depend on disease of the spine or of the hip-joint, two serious conditions which it needs the medical expert to discover and to treat.