300 THE URINE. 



1.6 grammes of the benzoylated cadaveriu from the collected urine 

 i)l' twenty-four hours. 



To demonstrate the presence of diamins, the method of Bau- 

 mann and v. Udranszky is most conveniently employed. To this 

 end, the collected urine of twenty-four hours or more is benzoylated 

 by shaking with benzoyl chloride in the presence of sodium hydrate. 

 As a general rule, 25 c.c. of the chloride and 200 c.c. of a 10 per 

 cent, solution of sodium hydrate are used for 1500 c.c. of the urine. 

 The resulting precipitate, which contains the earthy phosphates, the 

 benzoylated carbohydrates which are normally present in every 

 urine, and the greater portion of the benzoylated diamins, is then 

 filtered off, extracted with boiling alcohol, filtered, and the alcoholic 

 extract concentrated on a water-bath. This solution is then poured 

 into thirty times its volume of water. On standing, the benzoy- 

 lated diamins separate out in crystalline form, and are then freed 

 from adhering carbohydrates by repeated solution in alcohol and 

 precipitation in water. The process is continued until the desired 

 degree of purity is obtained. The resulting crystals are finally 

 filtered off, dried over sulphuric acid, and identified by their 

 melting-point and the contained amount of nitrogen. If both 

 diamins are present, the crystals lose their water of crystalliza- 

 tion at 120 C., and melt at 140 C. To separate them from 

 each other, they are dissolved in a little warm alcohol, and are 

 treated with twenty times as much ether. Benzoyl putrescin is 

 thus thrown down, while the cadaverin compound remains in solu- 

 tion. The crystals of the former melt at 175-176 C., while the 

 melting-point of the latter lies between 129 and 130 C. 



A small portion of the diamins remains in the first filtrate. To 

 isolate these, the liquid is acidified with sulphuric acid and ex- 

 tracted with ether. The ethereal extract is evaporated, and the 

 final solution, before congealing, placed in as much of a 12 per 

 <jent. solution of sodium hydrate as is required for its neutralization. 

 From three to four times as much of the alkali solution is then 

 added. On standing in the cold, sodium benzoyl-cystin separates 

 out, together with the benzoylated diamins. The crystals are fil- 

 tered off and placed in cold water. This dissolves the cystin com- 

 pound, while the diamins remain undissolved. They are soluble in 

 warm alcohol, and can then be separated from each other, as has 

 been described. 



