The presence of hematomas in the heart valves of new-born calves is today a widely known fact. Nevertheless, a survey of veterinary literature reveals only brief references, and, since in these the microscopic structure and possible origin of the hematomas have not been discussed, a study of these two points was undertaken. The literature describing hematomas in the heart valves of children was not consulted until the conclusion of the work on calves.
Kitt1 describes the hematomas as being bladders of blood or serous fluid, varying in size from a lentil to a pea, situated between the flat endocardial folds of the artioventricular valves, and raised somewhat above the surface of the valve. He gives no references but cites Glage and Kläger, whose observations agree with his own on slaughtered swine and young calves, and Gibson who had seen similar small cysts in lambs. Ostertag2 refers to the