An exhaustive treatise on our present knowledge of gout, the nature of its clinical manifestations and its treatment, cannot be confined to a short space; hence a brief exposition must forego amplification and touch only on those facts in the pathology of gout which are either of practical significance, or, because they possess an especial interest, are weighty factors in our conception of the nature of the disease. Furthermore, it is the object of this discussion to review carefully the changes which have been brought about during the last ten years in our ideas of theory and practice, and above all the questions of pathogenesis and therapy must be considered, for we believe it is in these, as we review the chapter of the diagnostic problems of gout, that there have been the most radical changes - and yet, in spite of this, more progress is to be desired even here. It is first important to define the exact limits of the term gout; for after reading many articles on the subject, the impression gained is that its clinical boundaries differ widely with various authors. To do this is a task at once pleasing and perplexing. The chief clinical difficulties in many cases consist in the determination of what is the sequel of gout and what is the sequel of a simultaneously existing arterio-sclerosis or chronic interstitial nephritis - a point to which I shall return later on. In gout we must make a sharp and careful distinction between an acute attack, or an acute general gouty manifestion and a chronic state of gouty diathesis. The latter is characterized by an increase of uric acid in the blood serum, and should not be mistaken for diathesis uritica. Clinically it is very easy to demonstrate a large increase in the quantity of uric acid in the blood, but the clinical signs of gouty diathesis are often unreliable. Without going into an exhaustive discussion of the boundaries of this condition, we will consider it sufficient for the identification of doubtful cases to name those criteria which possess the significance of stigmata. The experiment of Garrod, which unfortunately cannot be carried out on every borderline case,* possesses high clinical value, and there is identification by the tophi. To these the testimony of a typical case-history of gout adds its weight for the establishment of a diagnosis. Less important, but at times suggestive, is the gouty finger, which is a symptom of secondary importance, as is also the acne rosacea of the gouty patient. Furthermore, the association of gastro-intestinal or cardiac symptoms with a neuralgic or rheumatoid condition, in stout muscular, largeframed individuals of irritable temperament is very frequently significant. The demonstration of symptoms of chronic nephritis is an observation which is often valuable, especially when lead poisoning or al cholism, or both, are found in the history. Reale has lately shown that if the patient be gouty the indican test made with Obermayer's reagent gives a weaker reaction after boiling than before. For two cases of chronic gout we are able to confirm these results, but for all others our researches have shown this test to be in no way specific for gout. In our earlier investigations we were impressed with the parallel existence in the urine of a reducing, laevo-rotary, non-fermentable substance, together with a large amount of indican. From a recent inspection of our case-records we find among our observations on this laevo-rotary substance three cases of arthritis uritica - a considerable percentage of the total number of those showing laevo-rotation without fermentation. The symptoms of gouty diathesis here mentioned are certainly not present in every case; in still fewer is the gouty character of the trouble revealed by an acute paroxysm or by a chronic manifestation of gout. Nor does the increase in indican bear any essential relation to gout, since Grossman has shown by quantitative experiments conducted at my instigation, that after an abundant milk diet indican is promptly reduced to a minimum. Thus it is apparent that search must be made for each and every symptom which will betray the presence of gout. In a doubtful case of inflammation of the joints we were once able to make a diagnosis by the puncture test, recognizing in the fluid obtained crystals of acid sodium urate which demonstrated the gouty character of the arthritis.

* The thread test as described by Garrod (Gout and Rheumatic Gout, p. 86, London, 1876) is as follows: "Take from one to two fluid drams of the serum of blood and put into a flattened glass dish; - and to this add ordinary strong acetic acid, in the proportion of six minims to each fluid-dram of serum, which causes the evolution of a few bubbles of gas. When the fluids are well mixed introduce one or two ultimate fibers, about an inch in length, from a piece of unwashed huckaback or other linen fabric." After standing from thirty-six to sixty hours the uric acid crystals may be seen by means of a microscope or strong hand glass. This test has fallen out of use, probably because it, along with the literature of gout of that period, has been superseded in a large degree by later research. This test, however, offers a ready and quick method of detecting an excess of uric acid in the blood, where the exact quantitative estimations demand laboratory equipment only at the command of the specialist. The necessary blood serum is most easily secured by means of small cantharides plasters. Excluding interstitial nephritis and the lucaemias where there is an increase of uric acid in the blood, this test has a great value in the diagnosis of those cases of gout that present no characteristic symptoms such as tophi. [Editor.]