In a treatise by Dr. J.R. Buchanan, entitled "Outlines of Lectures on the Neurological System of Anthropology," are presented original ideas pre-eminently useful to the physician. His researches, and those of later writers, together with our own investigations, have greatly increased our professional knowledge. It is by such studies and investigations that we have been prepared to interpret, with greater facility, the indications of disease, and diagnose accurately from symptoms, which have acquired a deeper significance by the light of cerebral physiology. We are enabled to adapt remedies to constitutions and their varying conditions, with a fidelity and scientific precision which has rendered our success in treatment widely known and generally acknowledged. We annually treat thousands of invalids whom we have never beheld, and relieve them of their ailments. This has been accomplished chiefly through correspondence. When patients have failed to delineate their symptoms currently, or have given an obscure account of their ailments, we have been materially assisted in ascertaining the character of the disease by photographs of the subjects. The cerebral conformation indicates the predisposition of the patient, and enables us to estimate the strength of his recuperative energies. Thus we have a valuable guide in the selection of remedies particularly suited to different constitutions. In the treatment of chronic diseases, the success attending our efforts has been widely appreciated, not only in this, but in other countries where civilization, refinement, luxurious habits, and effeminating customs, prevail. This fact is mentioned, not only as an illustration of the personal benefits actually derived from a thorough knowledge of the nervous system, but to show how generally and extensively these advantages have been shared by others.