Prognosis was only too easy in this case, without inquiry into either the cause or the lesion. A few months later true angina occurred, and very shortly the patient died, after twenty-four hours' severe suffering. TREATMENT. Not the least advantage of the etiological standpoint of our survey of the disorders and diseases of the heart and arteries in middle and advanced life is the rational as well as hopeful line of treatment which it enables us to pursue. On the whole, we can control morbific influences more easily than we can alter pathological processes; and (what is of equal or even greater importance) a knowledge of the causes of disease often enables us to prevent what we could not possibly cure. For all that, the etiology of heart disease furnishes us with but one set of many invaluable indications for treatment. We must have also a clear mental picture of the pathological anatomy of the conditions we would attempt to modify--for instance, of the damage wrought by gout on the mitral valves and aortic arch, by syphilis on the coronary arteries, by strain on the walls of the different cardiac chambers. No less necessary is it for the practitioner to take into account, before proceeding to prescribe, the clinical characters and course of the case in hand. As I have said more than once already, a large proportion of the distress, disabilities and dangers attending degeneration of the heart are due to some additional or extrinsic disturbance--distension of the stomach, constipation, worry or exertion--which alone, not the pathological condition, calls for therapeutical attention. It appears, then, that the whole natural history of the diseases and disorders of the heart--and, I might add, of every individual case--has to be studied, and the value of its different parts absolutely and relatively estimated, before rational treatment can be ordered. How different will treatment be, if ordered on these principles, from the routine procedure of prescribing a little strychnine and digitalis for a man with oppression on exertion and a systolic bruit at the base of his heart! Let us begin this part of our subject with a brief consideration of preventive treatment, founded on a knowledge of the cause at work.