URIC ACID. 481 



sediments, urinary sand, and urinary calculi. Ammonium urate is con- 

 tained in lateritious sediment in but small amount, being formed in large 

 amount only as a result of ammoniacal decomposition of the urine (Fig. 

 154). Free uric acid occurs in normal urine only in the smallest amount . 

 It is, however, not rarely precipitated subsequently on standing (Fig. 

 153). and it is present, further, also in urinary sand and calculi. De- 

 ficiency of neutral phosphates in the urine favors the formation of uric- 

 acid sediment. 



The urine of the new-born is rich in uric acid (uric-acid infarct of the kidneys) . 

 The uric acid, together with its salts, is increased by marked muscular activity 

 attended with perspiration, also in the presence of catarrhal and rheumatic fevers 

 and such as are attended with derangement of respiratory activity; further, in 

 cases of leukemia with increased leukocyte-destruction and splenic tumor, granular 

 liver; and, finally, quite generally in connection with gastric and intestinal catarrh 

 following excessive indulgence in alcohol, after generous ingestion of cheese and salt 

 fish or salt meat, after administration of glycerin, and a diet containing nuclein. 

 Hypoxanthin fed to birds is eliminated in part transformed into uric acid. 



The amount of uric acid is diminished after generous ingestion of fresh fruits 

 (strawberries, cherries, grapes) or of quinic acid or alkaline salts of the vegetable 

 acids contained in them; further, after hot baths; also after ingestion of proteids 

 in large amount and after the administration of caffein, potassium iodid, sodium 

 chlorid, sodium carbonate, lithium carbonate, sodium sulphate, inhalations of 

 oxygen, gentle muscular exercise, though not after copious ingestion of water. In 

 cases of gout in which uric acid is deposited in the gouty nodules, its elimination 

 is slight. In the presence of chronic splenic tumor, anemia, and chlorosis, it is 

 diminished, particularly if no respiratory disorder is at the same time present; 

 and likewise in cases of epilepsy in advance of an attack. 



The Urates. With various bases uric acid forms principally acid 

 urates, which are soluble with difficulty in cold water and readily in 

 hot water. Neutral urates are transformed by carbon dioxid into acid 

 salts. Hydrochloric and acetic acids dissolve the combinations and 

 the uric acid separates in the form of crystals. 



Acid sodium urate, sodium biurate, has a neutral reaction, and ap- 

 pears as a uratic sediment (lateritious sediment) generally of a brick- 

 red color from uroerythrin (according to Hoppe-Seyler from urobilin) 

 less commonly it is between light gray and whitish in color in the 

 presence of catarrhal digestive disorders and of rheumatic and febrile 

 affections. Microscopically it appears as amorphous granules (Fig. 

 153, b). The sediment is dissolved by heating the urine. Not rarely 

 the sediment contains also the potassium-salt, which is entirely similar 



Acid ammonium urate is soluble with difficulty in water, is always 

 present, as a sediment, in ammoniacal urine, appears in reflected light 

 in the form of yellowish spheres of thorn-apple or morning-star shape- 

 in transmitted light of a darker color and is frequently accompanied 

 by triple phosphates (Fig. 154, a). 



Acid sodium urate and acid ammonium urate are recognized by 

 the separation of free uric-acid crystals in microscopic preparations, after 

 addition of a drop of hydrochloric acid. 



Acid calcium urate, occasionally present in urinary calculi, is a white 

 amorphous powder soluble with difficulty in water. Fused upon a 

 platinum plate, it leaves a residue of calcium carbonate. Rarely 

 magnesium urate occurs in urinary calculi. 

 3 1 



