Many difficulties confront the medical officer who has in his care large numbers of mental patients. In the first place, owing to the staffing problems which beset the majority of mental hospitals in this country, he is probably overworked. He has neither the time nor the energy to deal adequately with the mass of work which confronts him, and as a result his output is often not as efficient as it could be. Further, when dealing with large numbers, a physiological factor enters which is often overlooked. It is very difficult to register and retain the many small variations in behaviour which are so important in the understanding of a patient, when perhaps 350 or more patients have to be seen every day. There seems to be a definite saturation point beyond which images are not retained; indeed we know that this is so, but we rarely seem to take account of it. The very sameness of deteriorated and apathetic patients contributes to this state of affairs.