Lymphatics of the heart.

LYMPHATIC DRAINAGE of the heart has received little attention in the past but its potential importance has been recognized recently by several investigators.1-5 Review of studies of cardiac lymphatics4' 6 shows that many details of the anatomy of the system are still unknown, largely because of limitations of the technics of investigation. The small size and delicate structure of peripheral lymphatics and the presence of valves preclude their demonstration adequately by direct injection, and visualization in most instances has been by injection into living tissue of vital dyes which are removed by lymphatics. Using these technics, the most recent investigations have been those of Patek,9 Miller and associates,3 and Golab.10 An effective method for demonstrating lymphatics by direct application of hydrogen peroxide was described in 1922 by Magnus and Stubel" and in 1963 by Parke and Michels,12 and the purpose of this report is to present observations of the cardiac lymphatic system obtained by this means. Injection and clearing technics have been utilized in some instances also.