Let us suppose a horse to have been exercised; during that exercise, there is a determination of heat and fluids to the surface: the pores of the skin expand and permit the fluids to make their exit: now, if the horse is put into a cold stable, evaporation commences, leaving the surface cold and the pores constricted, so that, after the circulating system has rested a while, it commences a strong action again, to throw off the remaining fluids that were thus suddenly arrested; there is no chance for their escape, as the pores are closed; the skin then becomes dry and harsh, the "coat stares," and the animal has, in common parlance, taken cold, and "it has thrown him into a fever." Now, the cold is the real enemy to be overcome, and the fever should be aided by warmth, moisture, friction, and diffusables. If, at this stage, the cold is removed, the fever will disappear; but if the disease (the cold) has been allowed to advance until a general derangement or sympathetic action is set up, and there is an accumulation of morbific matter in the system, then the restorative process must be more powerful and energetic; constantly bearing in mind that we must assist nature in her endeavors to throw off whatever is the cause of her infirmities. Instead of attacking the disease with the lancet and poison,--which is on the principle of killing the horse to cure the fever,--we should use remedies that are favorable to life. It matters not what organs are affected; the means and processes are the same, and therefore the division of inflammation and fever into a great number of parts designated by as many names, and indicated by twenty times as many complications of symptoms which may never be present, only serve to bewilder the practitioner, and render his practice ineffectual. PLEURO-PNEUMONIA. As very little is, at present, known of the nature of this disease, we give the reader the views of Mr. Dun, who received the gold medal offered by the Agricultural Society for the best essay on this subject. "The causes of the disease, both immediate and remote, are subjects full of interest and importance; and a knowledge of them not only aids in the prevention of disease, but also leads the practitioner to form a more correct prognosis, and to pursue the most approved course of treatment. It is, however, unfortunate that the causes of pleuro-pneumonia have not as yet been satisfactorily explained. No department of the history of the disease is less understood, or more involved in doubt and obscurity. But in this respect pleuro-pneumonia is not peculiar: it is but one of an extensive class which embraces most epidemic and epizoötic diseases. And if the causes which produce influenza, fevers, and cholera, were clearly explained, those which produce pleuro-pneumonia would, in all probability, be easy of solution.