It is possible to make sheep 'neurotic' when positive and negative signals are closely similar or when long delayed reactions are attempted and when regular alternations for signals announcing a 'mild' electric shock and no shock are separated by equal rest periods. The three 'neurotic' sheep show overreaction to stimulation, extreme restlessness, irregular and rapid respiration. A detailed case history of a neurotic sheep showing a cardiac disorder is given. It is worth while to mention that this sheep showed a peculiar behavior even before it was used for experimentation in the laboratory. The cardiac disorder was characterized by rapid and irregular pulse, extreme sensitivity of the heart's action, spontaneous variation of its rate, premature beats and sometimes coupled rhythm. It would be better to call these sheep shocked, confused, traumatized or frightened than to use the misleading term neurotic. Some of the animals are under observation for seven years, but nothing is told about their instinctual life.