In accordance with a traditional viewpoint of the in ability of cardiac muscle to regeneration and cicatrization of necroses, many authors even failed to observe any "attempt" of cardiac muscle for regeneration, as expressed by the dedifferentiation of muscle fibres, nuclear division, isolation of myoblasts, growth of muscle buds, etc. The absence of similar processes has been pointed out in studies of the consequences of punctures, incisions and contusions of the cardiac wall (Bode, 1897; Eisberg, 1899; Tikhov, 1899; Klose, 1920; Moritz and Atkins, 1938; Ageichenko, 1947; Kolesnikov and Smirnova, 1949; Tähka et al., 1957; Warren et al., 1957; Wanick, 1961, and others), infarction (Karsner and Dwyer, 1916; Ikhteiman, 1934; Mallory et al., 1939, and others), cauterization (Walls, 1948) or coagulation of the myocardium (Harrison, 1947). In these studies the myocardium of different animals and man has been examined at a wide range of stages after in jury.