There is doubtless some force in these objections, especially in the second, for it does seem rather inconvenient to call by the same name so deadly a disorder as the worst form of angina, and so comparatively harmless a malady as some of those instances of chronic tendency to spasmodic pain of the heart which are not very uncommon, and in which the patient survives, perhaps, to an old age. Yet, after all, there is the greatest difficulty in drawing any rational line of distinction; for the basis of the affection seems the same in every case, whether pain or spasm be the predominant feature, and whether the course of the disease be long or short. All that appears to be necessary for its production is a certain originally neurotic temperament (with possibly some congenital weakness or some post-natal disease of that part of the spinal-cord centres which Von Bezold has described as furnishing three-fourths of the propulsive power of the heart) and the presence of almost any kind of difficulty or embarrassment of the action of the heart. The most common source of this embarrassment is perhaps failure of nutrition in the muscular walls of the heart, from disease of the coronary arteries. Indeed, it is not known that any organic change of the heart or great vessels, even of the slightest kind, is necessary to the production of angina; on the contrary, there is every reason to think that mere fatigue and depression may bring on the attacks in persons of a strongly nervous temperament. For my own part, I am inclined to believe, however that there really always is disease somewhere in the cardiac centre of the spinal cord, though that disease may consist in no more than a disposition to minute interstitial atrophy. But we shall say more about this presently. It is at any rate certain that cardiac neuralgia is always a most grave complaint, from the almost total uncertainty whether succeeding attacks will not involve a fatal amount of spasm. As for the expression angina pectoris, it is just one of those mischievous terms which, arising out of the mystified ignorance in which the elder physicians found themselves as to the pathology of internal diseases, have since been attached in turn to various definite organic changes, with none of which they had any essential connection; and it is therefore much to be wished that it could be altogether done away with. At the same time, there is so much that is peculiar in the case of cardiac neuralgia, owing to the importance of the organ affected, that it will be necessary here to treat not merely its symptoms, but also its diagnosis, prognosis, etiology, pathology, and treatment, in a separate and continuous manner.