MYOCARDIAL PATHOLOGY OF DOMESTIC RUMINANTS IN SOUTHERN AFRICA

tem autolysis, but the tissue should be examined micro­ scopically if a lesion is suspected. We have also observed irregular, pale areas in the ventricular walls. The only microscopical change that could be detected in these areas was a marked paucity of erythrocytes in the capil­ laries, and we believe that the pallor may be a mani­ festation of irregular blood redistribution caused by lo­ cal differences in the degree of rigor mortis. The size of the cardiac chambers and the thickness of the ventri­ cular wall can vary with the stage and degree of rigor mortis, and such variations may be confused with mo­ derate ventricuJar hypertrophy, atrophy or dilatation. Accurate assessment of ventricular hypertrophy or atrophy requires weighing of the ventricles, but few fi­ gures for ventricular weights of normal ruminants are available. Ventricular weights of Merino sheep in South Africa have been measured and analyzed in relation to body mass, sex and age 3 ?, but the results show consi­ derable variation, and it is unlikely that the weighing of hearts will prove useful in field investigations.