SEVEN FIGURESThe coronary arteries, like the weight, the form, and the histology of the heart, undergo continuous alteration with age. Concerning their macroscopical visible changes Gross ('21) has published detailed investigations. He found that the blood supply to the two ventricles was equal at birth, but that after the first decade the left ventricle was favored. Its supply, he thought, was definitely greater after the third decade, and after the fifth decade, the preponderance in its favor was striking. Consequently, anemia of the right side of the heart took place, which was for the most part relative, the difference depending not so much on the occurrence of degenerative processes as on, diminution in growth, at least in comparison with the left ventricle. He also pointed out the increasing thickness of the left ventricle with growth in comparison with the right. Campbell ('28) repeated Gross's investigations, using the same method, and believed he had verified Gross's results. Gross's contentions did not, as a matter of fact, remain unchallenged. Spalteholz ('24) stated that in his extensive researches he had not observed such changes. Whitten ('30), on the basis of a study of hearts which he treated by the method of corrosion, a method the