208 BACTERIAL POISONS. 



tate. For its separation from cadaverine and other aceom- 

 panying bases, see page 220. 



From the urine of cystinuria it is best obtained by pre- 

 cipitation with benzoyl chloride (BAUMANN'S method). 

 For this purpose about 1500 c.c. of urine are treated 

 with 200 c.c. of sodium hydrate solution (10 per cent.), 

 then 20 to 25 c.c. of benzoyl chloride is added, and the 

 whole shaken till the odor of the latter disappears. The 

 yellowish-white precipitate which forms may consist of in- 

 soluble phosphates, carbohydrates, polyatomic alcohols, and 

 diamines. The cystin compound is precipitated only in 

 concentrated solutions. The precipitate contains from a 

 half to two-thirds of the diamines present ; it is filtered 

 off, digested with warm alcohol, and the solution filtered. 

 The alcoholic filtrate is concentrated and then poured into 

 about thirty times its volume of cold water. The diamine 

 compounds then crystallize out. To separate the two dia- 

 mines they are redissolved in just sufficient warm alcohol 

 to effect solution, and this is then poured into about twenty 

 times this volume of ether. The putrescine benzoyl com- 

 pound is thus thrown out of solution. The filtrate from 

 this on concentration yields the cadaverine compound. To 

 isolate that portion of the diamines which remained in the 

 original filtrate with benzoyl cystin, it is acidulated with sul- 

 phuric acid and extracted with ether. The residue obtained 

 on evaporating the ethereal solution is first neutralized with 

 a 12 per cent, sodium hydrate solution, then mixed with 

 three to four times its volume of the same solution. The 

 precipitate which forms consists of the sodium . compounds 

 of benzoyl cystin and the diamines. It is washed with 

 sodium hydrate, and the two compounds separated by their 

 different solubilities in water the cystin compound is 

 readily soluble, that of the diamines insoluble. To purify 

 the benzoyl diamines they are dissolved in warm alcohol 

 and precipitated with excess of water. 



Putrescine (from putresco, to rot, to putrefy) is ;i watcr- 

 clear, rather thin liquid which fumes in the air and lias a 

 a peculiar semen-like odor, almost undistinguishahle from 

 that of cadaverine, and reminding one somewhat of the 



