Sir.—Dr. Barness has clearly focused on the concept I wished to emphasize about "diagnosis." Diagnosis represents the conscious effort of the diagnostician to classify something as this or that. Diagnosis does not just fall out from accumulated data. Furthermore, diagnosis has a functional component on which we determine how and when to treat.
Dr. Barness' citation of the separation of enzymatic defects by lysosomal disease by the Bradys and O'Briens supports my contention that diagnosis per se is not the end to be served. It is not making the proper diagnosis alone that will prevent or treat these diseases. It is the understanding of the mechanisms and the rational discussions that follow from this understanding that are important. It is when a diagnosis becomes an end in itself—when its sole purpose is to make oneself feel like Little Jack Horner—that a diagnosis is not necessary.
Memory banks or