If you have the good fortune to command a large clinic, remember that one of your chief duties is the tabulation and analysis of carefully recorded experience.
Rare diseases not only have interest for the clinical connoisseur but also may bring understanding to commonplace diseases. Collectors of clinical esoterica do indeed fatten their egos by the ability to pin a proper label on a patient with an obscure disease. Nonetheless, case reports of very rare conditions are needed to accumulate information which later may be synthesized. Unusual diseases may contribute to the knowledge of genetic mechanisms, and unsuspected physical and metabolic interdependences, and mischances in the development and in the fate of embryonic tissues. Patients with rare diseases and developmental anomalies may live a long time. This adds the dimension of time, if the subject is under observation for a period long enough to delineate the natural history of