=Uric Acid= (C_{5}H_{4}N_{4}O_{3}). Traces only of this are found in the normal herbivorous urine, yet it is more abundant when on a full dry grain diet, on milk (suckling) or on animal food. The dog kept on animal food has a large amount. =Pathologically= it is produced in the dog and even in the horse in fever, overwork and starvation, the animal living on his own tissues. Interference with oxidation in the lungs seems to produce it as an arrest in the transformation of albuminoids to urea. The neutral urate of soda remains in solution: the acid urate of soda is precipitated. _Test_: To the urine add one-fourth its volume of muriatic acid and set aside for 24 hours in a cool place. On the bottom and sides of the glass and on the surface of the liquid will be found the yellowish red acicular crystals of uric acid. =Hippuric Acid= (C_{9}H_{9}NO_{3}) is normally present in all urine, but is especially abundant in that of herbivora. The horse eliminates 60 to 160 grammes daily. It has been found to be increased by feeding on dandelion, carrots, clover, asparagus, apples, plums, benzoic acid, oil of bitter almonds, toluol, cinnamic or kinic acid. It is absent in sucking calves, and horses fed on grain devoid of husk. =Pathologically= it is increased in hyperthermia, icterus, some liver diseases and diseased kidneys. Test: Precipitate any albumen by nitric acid and boiling, then add hydrochloric acid which precipitates the hippuric acid in long needle-like crystals. Heated in a small glass tube it forms an oily liquid, and heated to redness gives off an odor of hydrocyanic acid (nitro-benzol) and carbon is left. This distinguishes alike from uric acid and benzoic. =Phenol= is produced by intestinal fermentation. The horse normally excretes about 3 grammes daily. Pathologically it appears in excess in indigestions, abscesses, softened discharging tubercle, pyæmia, and septicæmia. Test: Dilute solutions of ferric salts give a blue coloration. =Creatinin=, a product of metabolism of albuminoids, is found especially in the urine of carnivora and omnivora in health. It is pathologically increased when oxidation is interfered with, as in diseases of the lungs. Test: Add to the urine a very dilute solution of sodium nitro-prusside and then drop by drop some solution of caustic soda, when a ruby red color is shown and disappears again on boiling. Acetic acid changes to blue. =Acetone= (C_{3} H_{6} O) is found in the urine of healthy omnivora and carnivora and increased by excess of nitrogenous food. Pathologically it has been found in fevers with much blood change, in inanition, in cancer, in indigestions, and auto-intoxications. Test: To several c c. of urine add a few drops of iodo-potassic iodide solution and caustic potash when iodoform will be abundantly precipitated with its characteristic color and odor.