Isolation of the Encysted Form ofToxoplasma gondiifrom Human Skeletal Muscle and Brain

DESPITE the high prevalence of antibodies to toxoplasma among adults in the United States1 the parasite is rarely recognized in routine histologic sections obtained at autopsy. Since antibodies are demonstrable for many years (and perhaps for life) after acute acquired toxoplasmosis2 the question arises whether the stimulus to antibody formation in these persons is persistence of live parasites or of residual antigens. The first aspect of this question can be answered by the demonstration of living organisms in the course of isolation procedures. Because cysts of toxoplasma are often distributed sparsely throughout an organ it would be necessary in such . . .