Not only is the proximate cause of gout unknown, but the essential nature of the disease is still shrouded in obscurity; for the obliquity in trend of protein metabolism, manifested though it be by striking phenomena, is clearly only the outcome of some, as yet undetermined, derangement in the mechanism of _intermediary_ metabolic or bio-chemical change. This is, of course, but to restate the problem we are confronted with. Wholly to solve the enigma would postulate ability on our part to trace ingested foodstuffs through all their vicissitudes from the moment of entry into the blood or lymph-stream till flung out as effete matter through the various avenues of excretion; but, unhappily, we know the story only in part, its beginning and end, but not what lies between. We know much of the complex changes that take place in food prior to absorption, and of the _modus operandi_ of the latter not a little. Comparably, too, we can gauge the quality and quantity of end-products, the chemical outcasts, as they escape in the urine, sweat or breath, and largely how achieved; but of the intermediate steps between absorption and excretion we catch but a glimpse here and there. The sequestered path by which the inanimate molecules of food uprise to Life, and anon go down to decay and death, are still hidden. In other words, little do we know of the relationship of _labile_, or food-protein, to _tissue_ protein. True, the coarse fact of abnormal protein loss in _renal_ disease may be revealed in the urine, as likewise the waste of albumoses in _myeloma_, etc., and the incidence of amino-acids in disease of the _liver_. Similarly, the appearance of _cystin_ or of _alkapton_ in the urine bespeaks flaws in protein metabolism, failures in the normal disruption of amino-acids. All these are of the grosser anomalies of protein metabolism, but more subtle those of gout! Complex, in truth, the problem here presented, than which none more subtle exists in the realm of bio-chemistry. True, _quantitative_ variations in the content of the urine as to _urea_, _uric acid_, etc., undoubtedly bear a direct relation to _protein_ metabolism, but they give us little, if any, substantial clue as to the particular metabolic warp responsible. We see this particularly in regard to uric acid, so long accredited with an essential _rôle_ in gout. Thus we cannot, on the basis of the _variations_ in its _excretion_ only, presume to diagnose “gout.” This because even more extensive variations occur in _healthy_ persons. On the other hand, attacks of gout never occur when urates are absent from the _blood_. To reduce the amount of these urates is clearly then of importance, and obviously to this end a knowledge of their source is essential. We have an analogy to hand in diabetes, in which the somewhat similar problem relating to _glycosuria_ has been partially solved. REVELATIONS OF THE BIO-CHEMIST