All magical power lies dormant in man, and requires to be excited. (Compare Prof. James's "Law of Mental Energy" in the chapter on Mental Influence). This (need for excitation) is particularly the case if the subject upon whom we wish to operate is not in the most favorable disposition; if his internal imagination does not abandon itself entirely to the impression we wish to make upon him; or if he towards whom the action is directed possesses more energy than he who operates. But when the patient is well disposed or weak, he readily yields to the magnetic influence of him who operates upon him through the medium of his imagination. In order to operate powerfully, it is necessary to employ some medium; but this medium is nothing unless accompanied by internal action. Sydenham.--In the more modern period the deliberate use of the influence of the mind on the body is quite as clear. Undoubtedly the greatest of modern physicians, who well deserves the name of the English Hippocrates, is Sydenham. How much Sydenham realized that many of his patients' ailments could only be cured by occupying their minds with other things is seen in his writings. There is a characteristic story told by Dr. Paris in his "Pharmacologia" which illustrates this well and is a striking anticipation of what we are prone to think of as very modern views in these matters: This great physician, Sydenham, having long attended a gentleman of fortune with little or no advantage, frankly avowed his inability to render him any further service, at the same time adding, that there was a physician of the name of Robertson, at Inverness, who had distinguished himself by the performance of many remarkable cures of the same complaint as that under which his patient labored, and expressing a conviction that, if he applied to him, he would come back cured. This was too encouraging a proposal to be rejected; the gentleman received from Sydenham a statement of his case, with the necessary letter of introduction, and proceeded without delay to the place in question. On arriving at Inverness, and anxiously inquiring for the residence of Dr. Robertson, he found, to his utter dismay and disappointment, that there was no physician of that name, nor ever had been in the memory of any person there. The gentleman returned, vowing eternal hostility to the peace of Sydenham, and on his arrival, at home indignantly expressed his indignation at having been sent on a journey of so many hundred miles for no purpose. "Well," replied Sydenham, "are you better in health?" "Yes, I am now quite well; but no thanks to you." "No," says Sydenham, "but you may thank Dr. Robertson for curing you. I wished to send you on a journey with some object of interest in view; I knew it would be of service to you: in going, you had Dr. Robertson and his wonderful cures in contemplation; and in returning, you were equally engaged