In an earlier article we reported (Paulley et al., 1954) a series of cases with myocarditis believed to have been caused by toxoplasma infection. In this paper the cases previously described are again presented with the addition of photographs, photomicrographs, and electrocardiographic tracings. More details of the necropsies are included, and there are more data concerning other members of the patients' families. A further case probably of the same nature is recorded. Pseudocysts of toxoplasmosis have been observed several times in the heart muscle of patients dying of the acute generalized acquired variety of the disease (