A FORTY-THREE DAY AVOIDANCE SESSION.

A single Sprague-Dawley rat was subjected to an extended discriminated avoidance session in effect continuously for over 1000 hr (43 days). The longest possible shock-free interval that the subject could obtain without responding was 5 min. Since the subject did not sleep through shock, all resting or sleeping was interrupted at least once every 5 min by either a response or a shock. Neither the experimental (avoidance) animal nor a second animal which received all shocks not avoided by the first, gave any appearance of ill effects from the protracted session.