=Oxalic Acid= (C_{2} H_{2} O_{4}) appears to be secreted in small amount by healthy kidneys and it may also come from the splitting up of uric acid after secretion. It is augmented by feeding agents rich in oxalic acid (beets, fresh beans, asparagus, tomatoes). Pathologically it abounds in certain indigestions, and is associated with lameness and emaciation. Test: Add lime water to the urine, and the white oxalate of lime is precipitated. =Allantoin= (C_{4}H_{6}N_{4}O_{3}) is found in the urine of sucklings (calves) during the first few weeks of life, in pregnancy and when on a meat diet. It diminishes with the increase of vegetable food. =Xanthin= (C_{5}H_{4}N_{4}O_{2}) is found in urine as a result of imperfect oxidation of nitrogenous matters especially, which would otherwise pass into uric or hippuric acid. Its immediate antecedents in such transformation are guanin and hypoxanthin or sarkin. It is a rare constituent of urinary calculus. =Hypoxanthin= (C_{5}H_{4}N_{4}O) is produced from fibrine in gastric and pancreatic digestion and in putrefaction, and is especially abundant in leucæmic subjects. =Cyanuric Acid= (C_{20}H_{14}N_{2}O_{6}) occurs in dog’s urine. =Leucin= (C_{6}H_{13}NO_{2}) and =Tyrosin= (C_{9}H_{11}NO_{3}) are products of pancreatic digestion of proteids, and the former occurs normally in the spleen, thymus, thyroid, liver, salivary glands, and urine. Both are present in large amount, in the urine, in acute atrophy of the liver. Test for leucin: Evaporate carefully to dryness with nitric acid: the residue, if leucin, will be almost transparent and turn yellow or brown on the addition of caustic soda. If now heated with the soda it forms an oily drop. Test for tyrosin: treated with strong sulphuric acid, gently warmed and chloride of iron added, it gives a violet color. =Albumen= is an important morbid constituent of urine, which appears in a great variety of diseases (nephritis, pneumonia, epilepsy, anæmia, leucæmia, diabetes, hæmaturia, hæmoglobinuria, hydræmia, infectious lung diseases, cardiac obstruction, venous stasis in the kidney, dermatitis, burns, lesions of the crura cerebri, floor of the fourth ventricle, spinal cord, or renal vaso-motor nerves). It also occurs after violent exertion, in poisoning by strong acid, phosphorus, arsenic, lead, mercury, opium or alcohol, and when an excess of albumen is injected into the blood. All forms of albumen may enter the urine, but the most common are serum albumen, globulin of serum, propeptone and peptone. A simple test is to acidulate the urine with acetic acid and boil: if the precipitate does not dissolve on addition of nitric acid, it is albumen. Sulphosalicylic acid added to the urine will cause a precipitate in urine containing only ¹⁄₅₀₀₀₀ of albumen.