CREATININ. CHLORIDS. 167 



with ether, which removes the last traces of benzoic acid. Sepa- 

 rate the aqueous solution of glycocoll from the ether, add to it 

 barium carbonate until the sulphuric acid has been neutralized, 

 filter, wash and evaporate the nitrate until the glycocoll com- 

 mences to crystallize. It has a sweet taste, whence its name. 



CREATININ. 



363. To separate the creatinin from urine add to 100 cubic 

 centimeters of the latter 5 to 6 cubic centimeters of saturated solu- 

 tion of sodium acetate, then 20 to 25 cubic centimeters of a 

 saturated solution of mercuric chlorid. The precipitated sul- 

 phates, phosphates and urates are now to be filtered out and the 

 filtrate allowed to stand for twenty-four hours. There is a 

 separation of the creatinin combined with mercury as transparent 

 globules. Make sketches of its appearance under the microscope. 



CHLORIDS. 



In the urine the excreted chlorin, of which there is 

 normally in a day 6 to 10 grammes, is united principally 

 with sodium. There is a small part with potassium as 

 potassium chlorid. The excretion of chlorids in health is 

 increased with salt food and with large quantities of drink. 

 Chlorids are necessary in the fluids of the body' for the 

 proper performance of their functions. When more chlorin 

 is required by the body the chlorids are held back by the 

 kidneys from the urine. When there is a less demand in 

 the body the kidneys excrete the chlorids. Thus, in pneu- 

 monia and other diseases, where there are serous exuda- 

 tions, the chlorids are withdrawn from the circulation to 

 form the constituents of these fluids, as is shown by their 

 decrease in the urine. When the pathological exudations 

 are absorbed the amount of urinary chlorids increases. In 

 fevers there is a decrease in the chlorids of the urine until 



