154 THE PHYSIOLOGY OF URIC ACID 



urine of patients with obstruction of the pylorus 

 and gastric dilatation, on an oxalate-free diet. 



When ammoniacal fermentation of urine takes 

 place, as on standing, any oxalate crystals present 

 are rapidly dissolved and disappear. 



The oxalate calculus is by far the most important 

 variety occurring in the kidney. B. Moore has 

 shown that a pure uric acid stone is found only in the 

 bladder, and that all renal calculi are composed for 

 the most part of calcium oxalate. This is fortunate 

 for the :^-ray diagnosis of the condition, and as it is 

 comparatively easy to control the oxalate excretion, 

 it makes it possible for us to advise the patient how 

 to avoid a relapse after operation. To draw the 

 practical lessons from our study, it is evident that 

 any patient suffering from oxaluria should abjure 

 the use of green vegetables, and fruits should be 

 taken sparingly. If he is obeying directions, a fresh 

 specimen of his urine, mixed with an equal amount 

 of spirit and allowed to stand, will deposit only a 

 few small crystals of oxalate, and a specimen without 

 the addition of spirit will show no crystals even on 

 centrifugahzing. Occasionally, however, one may 

 find a case in which oxaluria persists even on a milk 

 diet. We must then restrict the sugars and starches 

 of the diet, and give remedies calculated to diminish 

 fermentation in the stomach and intestines. 



If patients object to dietetic restrictions, potassium 

 citrate will often reheve, both by acting as a diuretic, 

 and by making the urine alkaline, thus dissolving 

 the crystals. 



