It should be expected that such careful and pains-taking experiments, as are necessary to establish a science, will be preceded by intuitive judgments and accredited observations, which may be, for a time, the substitutes of those more abstruse in detail. We have, in accordance with popular usage, treated the organs of thought as having anatomical relations. The views which we have presented in this chapter may seem speculative, but the facts suggesting the theory demand attention, and we have attempted to gather a few of the scattered fragments and arrange them in some order, rather than leave them to uncertainty and greater mystery. It is by method and classification that we are enabled to apply our knowledge to practical purposes. Possibly, to some, especially the non-professional, an allusion to the fact that cerebral physiology contributes to successful results in the practice of medicine, may seem to be an exaggerated pretension. None, however, who are conversant with the facts connected with the author's experience, will so regard this practical reference, for the statement might be greatly amplified without exceeding the bounds of truth. Physicians generally undervalue the nervous functions, and overlook the importance of the brain as an indicator of the conditions of the physical system, because they are not sufficiently familiar with its influence over the bodily functions. Pathological conditions are faithfully represented by the thoughts, and words, when used to describe symptoms, become the symbols of feelings which arise from disease. How few physicians there are who can interpret the thoughts, and glean, from the expressions and sentences of a letter, a correct idea of the morbid conditions which the writer wishes to portray! Each malady, as well as every temperament, has its characteristics, _and both require careful and critical analysis_ before subjecting the patient to the influence of remedial agents.