Numerous recent articles have served to call attention to the increasing number of persons who are dying from heart disease. Thus, in the registration area of the United States, the number of deaths from heart disease per hundred thousand of population has gradually increased from 132 in 1900 to 185 in 1925. The two reasons that have been given for this increase are the strenuous life of today and the increased length of life, which permits more people than ever before to reach the "heart disease" age. I herewith present an explanation for at least a portion of the increasing mortality from heart disease. It is a reason which, so far as I know, has not before been presented. This explanation furthermore offers great hope for a reduction—possibly a considerable one—in the number of cases of this disease in the course of the coming years. Heart disease is in large