COMPOUNDS OF ORGANIZATION. 



change from the atmosphere, except a slight deliquescence 

 in very damp weather. In a strong heat it melts, and is 

 partly decomposed, and partly sublimed without change. 

 It is very soluble in water and alcohol. The fixed alkalies 

 and alkaline earths decompose it ; it unites with most of the 

 metallic oxides, and forms crystalline compounds with the 

 nitric and oxalic acids. 



Urea is readily decomposed by boiling its solution in 

 water, and supplying new water as it evaporates. Carbo- 

 nate of ammonia is disengaged, acetic acid is formed, and 

 some charcoal precipitated. It is considered as containing 

 a greater quantity of azote than any of the animal princi- 

 ples already enumerated. Its ingredients have been vari- 

 ously estimated, owing to the impurity of the urea, and the 

 imperfection of the art of analysing animal principles. Dr 

 PROUT and M. BEHAKD give its contents as follows: 



Urea exists in the urine of the mammalia, when in a state 

 of health. In the human subject, it is less abundant after 

 a meal, and nearly disappears in the disease called Diabetes, 

 and in affections of the liver. 



7. Sugar. This well known substance exists in consi- 

 derable abundance in milk, and in the urine of persons 

 labouring under Diabetes. In the latter fluid, it is to be 

 considered as a morbid secretion of the kidneys, occupy- 

 ing the natural situation of the urea. In milk, however, 

 it exists as a constituent principle, and may readily be ob- 

 tained by the following process : Evaporate fresh whey to 

 the consistence of honey, dissolve it- in water, clarify with 

 the whites of eggs, and again evaporate to the consis-. 



