I am the more particular on this point, as some authors on the subject of insanity seem almost to discourage all mental exertion whatever; whereas, we should never lose an opportunity of repeating the common observation, that the judicious exercise of mind, as well as body, is equally conducive to health and strength, as it is to mental improvement and worth. Rightly to apportion and conjoin the exercise of the feelings and understanding, as well as of the corporeal frame, constitutes the whole of Physiology as applied to health. When the civil duties of life are performed from right motives, we then are obedient to the first law of nature, as well as of the Decalogue: then all is healthy co-operation—all portions of the system have their fair proportion of exercise—none are over-worked, neither in the individual nor in the mass—neither in body nor in mind, as we at present see to be the case, singly and collectively: everywhere the effect is similar, destructive alike of all healthy, mental, and corporeal energy, and of all the sweet ties and charities of life which bind families and societies together. It is remarked by Dr. Arnold and Dr. Penel, that most mathematicians and philosophers have not only lived to an advanced age, but have enjoyed good health, and have been exempt from mental diseases. Perhaps the number of such men vouchsafed to the world, has been too inconsiderable to enable us to form any correct comparative estimate between them and the rest of mankind, yet reason proclaims it true; and as far as medical statistics furnish us with facts, they all tend to confirm the truth. Certain it is, that nothing conduces so much to health and long life as conduct, well regulated, and a mind habitually preserved in a state of intellectual calmness.