As a rule, this _acute gouty polyarthritis_ occurs in individuals who have already experienced articular paroxysms at the classic site; but in the subsequent polyarticular attacks the _toe_ joints are often unimplicated, and the disease is located in the larger articulations—the knees, ankles, wrists, or elbows. Herein resides the difficulty of diagnosis in these cases: the likelihood of confusion with other polyarthritides. Confronted then with an _acute polyarthritis_ of obscure nature marked by pain, redness, swelling, and pyrexia, what are the points necessary to establish it as being of gouty origin? The sex and age should be noted, also the heritage, habits, and occupation. A history of _previous attacks located in the big toe_ would be of prime value. The presence of a cardiac _valvular_ lesion, while it would suggest a previous attack of _acute rheumatism_, would in no wise negative the possibility of the subject developing _gout_ in later life. Here I may say that if the subject is over thirty-five and has never had acute rheumatism or acute gout, it is much more likely at his time of life that his _acute polyarthritis_ is of _gouty_ than of rheumatic origin. As to the character of the pyrexia, it is usually of _low_ grade; but if the condition be _afebrile_, it is even more suggestive of a _gouty_ arthritis. But recollect, too, that the pyrexia in _gonococcal_ arthritis is also of low grade or absent. There is nothing distinctive of _gout_ either in the character or distribution of the articular lesions. The ankles, knees, hands, wrists, are most commonly involved, much more rarely the elbows, shoulders, or hips. Naturally the local changes will differ according to the joint involved and the structures implicated; but these local variations in appearance, including œdema, may all be met with in any form of _infective_ arthritis. As to _uric acid excretion_, Osler, who was deeply interested in this type of arthritis, held that any _lowering_ of the ratio of the _uric acid_ to the _urea excretion_ would be significant of gout. Also we should, as these cases of acute gouty polyarthritis are of the nature of successive paroxysms (“series et catena paroxysmulorum,” to use Sydenham’s expression), note _any variations in the uric acid output_ ensuing _pari passu_ with their rise and wane.