Every observing person whose experience extends past 40 knows that heart disease is constantly developing among his contemporaries who are otherwise healthy. Surprise is often expressed that this man or that, in spite of what seemed to be right living, has become a victim of heart disease.
The slightest consideration leads to the belief that there is some active or hidden agent working to cause heart disease and hardening of the arteries, and a little examination shows that the causes are not those usually assigned. The healthy old drunkard disproves alcohol as a cause. Rheumatism more often attacks the young, and in later life generally spares the heart and blood-vessels. Men who really overwork are not so numerous as is often thought, and worry, while a great cause of heart disease, is indirect in its effect.
The fact is constantly appearing in the literature of the day that circulatory disease,