ACTION OF THE KIDNEYS. 645 



ful to the animal economy, are immediately eliminated by the 

 kidneys. 



Professor Liebig, in his late work on Animal Chemistry, p. 136, 

 has made a remarkable observation. Protein -f 3 atoms water 

 may be resolved into choleic acid and urate of ammonia. 

 Protein is, . C 48 H 36 Az 6 O u 



3 atoms water, . H 3 O 3 



Total, . C 48 H 39 Az 6 O 17 



Choleic acid is, C 38 H 33 Az O 11 



Uric acid, . C 10 H 4 Az 4 O 6 



Ammonia, . H 3 Az 



Total, . C 48 H 40 Az 6 O 17 



Differing only by an atom of hydrogen. It would not be sur- 

 prising, then, if the uric acid and urea as well as the choleic acid 

 were formed in the liver. 



It has been long known that in diseases of the liver the quan- 

 tity of urea in the urine is diminished. Is it not possible that the 

 albumen of blood is decomposed into bile and urea ? The urea 

 and uric acid are rich in azote, while the bile contains but little. 

 Whether this conjecture be well or ill founded, there can be 

 little doubt that the formation of these two substances must be 

 the result of the decomposition of the constituents of blood, to 

 form some secretion of importance to the animal economy. The 

 importance of the liver as a secreting organ is obvious from the 

 great derangement of the system which takes place when it is- 

 diseased. 



Liebig conceives that the matter of bile is absorbed by the 

 lac teals, and employed in the production of heat by its union 

 with oxygen during the function of respiration. But certainly 

 this cannot be the case unless the bile undergoes decomposition. 

 For in the disease called jaundice, when the bile is absorbed in- 

 to the system, the skin and eyes are tinged yellow. The me- 

 thods of determining the quantity of bile secreted are so vague 

 that no reliance can be placed on them. 



Chossat has shown that the quantity of solid matter in the 

 urine increases with the food, and is proportional to it, supposing 

 the whole food to be digested. 



