A fairly complete search through the literature reveals no accurate knowledge or satisfactory explanation of the pathologic process which is the basis of the progressive development of chronic cardiovalvular disease. By chronic cardiovalvular disease is meant a chronic, nonbacterial, nonrheumatic disease of a heart valve, or of valves, which is characterized at the necropsy by marked fibrosis of the valve cusps or flaps sometimes causing marked distortion or stenosis, at times with calcareous deposit in the valves, but unaccompanied by vegetations other than very small ones, such as are described in this paper.
The histologic changes in simple or verrucous endocarditis are well known, as are those of the terminal stage of the process which is usually, through improperly, termed "chronic endocarditis." The cause of the progressive changes in nonbacterial lesions of the heart valve, and the mechanism of these changes, is very imperfectly understood.
It will be necessary, before