The power of concentration is the first thing necessary to develop healing power. The healer must be able to hold steadily the thought for the cure of his patient whenever he requires. Concentration is most difficult, but if this is accomplished, there is nothing that one cannot accomplish. It is useless to try and cure the patient by any process, however successful and good it may be, if there is no power of concentration. The work of the mind in healing is much greater than in anything else, for it is using the power of the mind on matter; and matter, which has been a disobedient slave of the spirit for ages, through the mineral, through the vegetable, and even through the animal kingdom always rebels against being controlled.