FOUL AIR AND DISEASE OF THE HEART. 185 



until they have passed to the lungs, and have there received the vivi- 

 fying influence of oxygen, can they enter into the real composition of 

 the blood, and thus become active, exciting, disposable constituents 

 of it. 



" Like begets like " in very many instances. This axiom is true in 

 relation to diseases of the heart. The rich, stimulating blood of the 

 left ventricle urges, feeds, and actively supports any disease which 

 may arise at that point ; while the poor, impoverished, fouled, tainted, 

 and attenuated blood which flows through the cavities of the right 

 heart favors disease of a correspondingly low and degenerate char- 

 acter. 



So long as the body is rapidly built up and as rapidly pulled down, 

 disease of the left heart maintains an active character ; but when the 

 balance between nutrition and waste is destroyed when nutrition be- 

 comes less active, while waste remains the same, or is more active than 

 before disease of the left heart loses more and more of its active char- 

 acter, and approximates more and more in its nature to disease of the 

 right heart. In many this change begins at the age of forty ; in others, 

 not until five or ten years after that period. Thenceforward the ten- 

 dency to inflammatory disease of the left heart declines the tendency 

 to degeneration increases. "With the gradual declination of the one 

 tendency and the gradual increase of the other, a period is at length 

 reached when active inflammatory disease ceases, as a rule, to affect 

 the left heart. At this juncture the left and right sides of the heart, 

 hitherto dissimilar in their tendencies, are in this respect almost as 

 one. The active tendency of early life has given place to the passive 

 tendency of advancing years inflammation to degeneration. 



Acute rheumatism a fruitful cause of cardiac disease in the earlier 

 periods of life is seldom seen beyond the age of fifty. I have, how- 

 ever, attended a case of acute articular rheumatism at the age of sev- 

 enty-five ; but such an instance was an exception to the rule. After 

 fifty, acute rheumatism gives place to a form of rheumatism which 

 slowly produces rigidity of the coats of the blood-vessels, hardens and 

 contracts the tendons, thickens and renders stiff and rigid the liga- 

 ments of the joints, hardens and lessens the articular cartilages. 



Thus, then, according to a law of Nature, the ultima linea of life 

 ends in degeneration. 



Apart from the influence of this law, can any accidental, casual, or 

 avoidable circumstance 'favor this immutable tendency to degeneration, 

 speaking more particularly in reference to the heart ? Yes ; many cir- 

 cumstances are daily, hourly, momentarily doing this. Thousands 

 annually perish from heart-disease, whose lives might and would have 

 been prolonged had but proper attention been given to the simple 

 laws of Nature. These laws demand attention to the three great vital 

 functions the action of the brain and nervous system, respiration, and 

 circulation. 



