468 JACOB ROSENBLOOM 



- ' 



Weiske in a case of leucemia in an animal ; and Cotterereau in the urine 

 of a boy. 



The chemical nature of xanthin was first studied by Liebeg and Woh- 

 ler, who analyzed a stone removed by the older Langenbeck. The stone 

 was removed from an eight-year-old boy and was the size of a hen's egg. 

 They were able to show that this stone was composed of the same substance 

 that Marcet had described, linger was able to verify these results. 

 Langiere recorded the third case of xanthin calculus. Lebon describes the 

 fourth case and records a stone composed of xanthin, uric acid, phosphates, 

 and calcium. Hoppe-Seyler mentions the fifth case, Dulk the sixth, and 

 myself the seventh. 



As xanthin is one of the mother substances of uric acid, it is quite 

 possible that the same sort of metabolic defect is present in these cases as 

 in the uric acid deposits. 



Cystin Calculi 



These calculi are very rare and of great interest. The condition of 

 this metabolic defect will be described under cystinuria as individuals suf- 

 fering from this condition are those that are apt to develop cystin calculi. 



HI. Dietetic and Medicinal Treatment of the Various 

 Varieties of Urinary Calculi 



(a) Phosphate Calculi. The dietetic indications are to diminish the 

 intake of calcium, thereby putting the phosphate in a more soluble form. 

 Foods rich in calcium are therefore to be avoided, such as milk, fish, eggs, 

 beer, wine, liquor and fruits, while meat, potatoes, cereals, broths, sugar, 

 sweets and puddings are allowed. 



Medicinally hexamethylenetetramine and acid sodium phosphate or 

 citric acid should be given. Diuresis should be promoted by advising the 

 use of large quantities of water. Of course in those cases where hyper- 

 acidity of the gastric juice is present, this must be treated along appro- 

 priate lines. 



(b) Uric Acid Calculi. It will be remembered that the uric acid of 

 the urine has a twofold origin, the endogenous, derived from the metab- 

 olism of the tissues, and the exogenous, derived from the decomposition 

 of the food. The endogenous is constant for the same individual and is 

 uninfluenced by diet, while the exogenous can be profoundly influenced by 

 diet. It must also be remembered that the precipitation of uric acid from 

 the urine does not depend entirely upon the amount present, but very 

 largely on the chemical relationships determining the formation in which 

 the uric acid is excreted, and that in order for it to remain in solution in 



