CALCIUM AND PHOSPHORUS STUDIES

When is rickets to be designated as late rickets? Schmorl1writes: By late rickets I understand all cases which come under observation in the later periods of growth (after the end of the fourth year). Under the conception of late rickets are to be included, therefore, not only those cases in which the disease began in the earlier growth periods but never disappeared—persistent rickets—but also those cases in which rickets developed for the first time in the later periods of growth—late rickets in the narrower sense. Strictly speaking, only the rickets which first develops in the later growth periods merits the name of late rickets. If, however, I make the conception of late rickets as broad as I do, it is because of the impossibility in many cases of making a clear separation between persistent rickets and late rickets. Schmorl, therefore, makes age the sole criterion. Schmorl selects the