Unilateral subtotal collicular and, large but not small, unilateral posterior cortical lesions in rats produced ipsiversive progression tendencies in a visual task. However, no support could be given to the view that the progression tendencies following unilateral collicular lesions are in part a reflection of contralateral visuosensory-field deficits. Thus, performance of a light-dark task was equally good when vision was restricted to the eye leading to the damaged colliculus as when restricted to the eye leading to the undamaged collicullus. la addition, bilateral collicular lesions had no effect on performance of either the light-dark or a stripes discrimination task. The study indicated the need for caution in basing interpretations of the nature of vision on simple response tendencies.

Two hundred and fourteen cases of spinal dysraphism were studied to investigate the relationship of sensory level and renal damage. It was found that in 72 cases with a high sensory level of T12 and above, 45 cases (62%) had renal damage which was the cause of death in 12; in 142 cases with a low sensory level of L1 and below, 40 cases (28%) had renal damage which was the cause of death in only 2. A palpable bladder and reflux were associated with renal damage in the cases with a low sensory level but some additional factor appears to operate in those with a high sensory level. Other reasons for the poor prognosis in these cases are discussed. The critical level in the spinal cord at which the prognosis for renal damage sharply changes coincides with the sympathetic outflow to the renal tract (T12-L1). Disruption of the spinal cord at or above the renal outflow may be a determining factor in prognosis.

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