The investigation of the chemistry of the blood during the past decade has brought us somewhat nearer to the elucidation of certain clinical problems. We know considerable of the etiology of diseases and still more of their end-results, their pathology. But as to the chemistry of their development and progress, little is known. Particularly is this true of the so-called endogenous, or, perhaps more correctly, the metabolic diseases. It is in the latter group that the most satisfactory chemical results have been obtained.
Certain metabolic alterations, notably the elimination of the catabolic products, are definitely determinable by laboratory methods; and no matter how divergent may be the views on points such as technic, interpretation of results, and consideration of normal or of physiologic factors varying the normal, the findings are valuable as indicating the nature of the disturbances in the process of the abnormal production or of the elimination of