Our views concerning carbohydrate metabolism in health and disease are constantly changing. New facts are gradually being added to our knowledge of the subject. In attempting to explain the causes of diabetes we have been forced to abandon various theories in succeeding decades. The accumulated results of innumerable investigators may make obsolete to-day a theory which seemed to hold good yesterday. Profiting by this experience, we must ever bear in mind that we should not be carried away by any new theory that is advanced to explain diabetes, even though it may be based on accurate experimental research.
In all cases of diabetes, with the exception of the experimental phlorizin diabetes, it is generally conceded that the appearance of the sugar in the urine is dependent on the existence of a hyperglycemia. It has generally been held that the glucose content of the blood normally ranges between 0.1 and 0.2