Chemical Changes in Animal Organism. 285 



functions, a relatively large proportion of ammonia is 

 excreted in the urine (as ammonium salt). Thus in cer- 

 tain cases of cirrhosis of the liver the amount of ammonia 

 in the urine is abnormally high ; in such a case the deter- 

 mination of the distribution of the nitrogen amongst the 

 urinary constituents is of importance for the purposes 

 of clinical diagnosis. 



In cases involving inflammation of the kidneys, 

 Bright's disease, etc., part of the urinary nitrogen is 

 excreted in the form of protein, which is in negligibly 

 small amounts in normal urine. Hence the value of 

 estimation of proteins in the urine when diseases of this 

 character are suspected. 



Finally, only very small amounts of dextrose are ex- 

 creted in the urine of healthy individuals ; diabetic 

 patients on the other hand, who are unable to utilize 

 their carbohydrates normally, can excrete quite large 

 amounts of this sugar, together with /3-hydroxybutyrie 

 acid, ace to-acetic acid, and acetone in certain cases. The 

 examination of the urine for these substances can throw 

 much light on the course of the disease. 



It has only been possible within the scope of these 

 pages to treat in a very casual manner the subject of the 

 initial and final products of mammalian metabolism, of 

 which only a certain number have been taken into con- 

 sideration. The few examples, chosen in a somewhat hap- 

 hazard manner, will illustrate the importance of the subject, 

 and show the intimate bearing of chemical knowledge on 

 certain problems connected with health and disease. 



Part II. Intermediary Metabolism in the Animal Body. 



So far attention has been directed towards the con- 

 sideration only of the initial and final products of meta- 

 bolism, and only a few references have been made as to 



