3. Swelling and thickening of this fibrous structure, and conse quent bulging of the endocarclium over the seat of the swelling; 4. Rubbing of one swollen segment against another; 5. Roughening of the endocardial surface as a result of this fric tion.
It is not till all this has taken place that a murmur is developed or a diagnosis made; so that the rheumatic poison has been exercis ing its action on the heart for one or two days before there are any signs of its doing so. If the salicyl compounds be given to a man just after the fibrous textures of the heart have begun to suffer, they are not given in time to stop the action of the rheumatic poison on them, or to prevent proliferation of the cellular elements; they are not given in time, therefore, to prevent swelling of the valves and rubbing of their segments, and, consequently, not in time to prevent those changes on the endocardial surface to which that rubbing gives rise.
The development of an endocardial murmur after the commence ment of salicyl treatment seems to indicate that this treatment pos sesses no power to prevent cardiac complications. More careful in quiry shows this conchision to be hasty, and probably erroneous; for not only is some time required for the development of an endocardial blow, but, as we know from what is observed in rheumatic inflamma tion of the joints, it takes another day to get the full action of the salicyl compounds. A man may begin to take these compounds on Monday, and on that day the heart's sounds may be quite normal. On Tuesday his joint inflammation may be much better; but there may be an endocardial blow. From the coincident decline of the arthritic and development of the cardiac symptoms the inference might naturally be drawn, and has in several cases been drawn, that the salicyl compounds have no power to prevent cardiac complica tions in rheumatism. But a careful examination of all the circum stances of the case would lead to a more cautious, if not different, conclusion. Any prophylactic property possessed by the salicyl compounds in rheumatic inflammation of the heart must be due to their destructive action on the rheumatic poison. But this saving action cannot be got unless they are given before the poison has be gun to act on the heart; for with the commencement of morbid change in that organ terminates the period of possible prophylaxis.
But even if the start were fair and equal—even if the salicyl treat ment commenced at the same moment that the rheumatic poison be gan to act on the fibrous textures of the heart—the morbid process would still have the advantage, for probably twenty-four hours would elapse before there could be introduced into the system the quantity of the salicyl compounds requisite to the destruction of the poison.
During these twenty-four hours the rheumatic poison would have time and opportunity to cause such change in the fibrous textures as would lead to thickening of the valves, to consequent friction of their segments, and to the development of the signs of endocarditis ; while the continued activity of the inflamed tissues would prevent the de cline of the inflammation which might otherwise be expected to follow the destruction of the rheumatic poison.
It is impossible to state with exactitude either, on the one hand, the time which, in a given case, must elapse between the commence ment of cardiac inflammation and the development of an endocardial blow ; or, on the other, the quantity of the salicyl compounds requisite to destroy the rheumatic poison. The former must vary with the acuteness of the attack, the latter with the amount of poison in the system at the commencement of treatment, and with the stage of the disease at which treatment commences. In no given ease can we posi tively assert that the absence of heart complications is due to the preventive action of the salicyl compounds. All that we can do is to satisfy ourselves, first, as to the mode in which the heart complica tions are brought about; and, second, as to the manner in which the salicyl compounds act. Having done this, we are in a position to judge as to whether or not they are likely to possess any prophy lactic properties.
It has been abundantly proved that the salicyl compounds do pos sess the power of arresting and cutting short the course of rheumatic fever. This means that they possess the power not only to allay the inflammation which already exists, but also to prevent that which would certainly arise, either in those joints which have already been affected, or in others if the attack were prolonged. If we admit their power to prevent rheumatic inflammation of the joints, we must also admit their power to prevent similar inflammation of the heart. If the view which has been advanced as to their mode of action be cor rect, they cannot fail to prevent cardiac complications, if only they are given in sufficient quantity to destroy the rheumatic poison be fore this has begun to affect the heart. The chief obstacle to their doing so is the early stage at which the heart is apt to suffer. It is only in a minority of cases that time and opportunity are given to get the full action of the salicyl compounds before the heart is affected. This is specially the case in hospital practice, in which the patients seldom come under notice before the disease has existed for the best part of a week.