174 



BACTERIOLOGICAL CHEMISTRY 



LESSON X 



(14) The crystals of these two substances may be purified 

 by dissolving them in spirit and allowing them to crystal- 

 lise out again. 



I. Tetramethylene-diamine 

 (putrescine). 



(a) Dissolve crystals in a solu- 

 tion of equal volumes of alcohol 

 and concentrated hydrochloric acid. 



(6) Heat in water bath at 45 C. 

 for twelve hours. 



(c) Dilute with water, till no 

 more precipitate appears. 



(d) Filter. 



(e) Filtrate shake with ether, 

 and separate the ethereal extract. 



(/) Slowly evaporate the ethereal 

 extract : crystalline mass, with 

 difficulty soluble in alcohol = 

 hydrochlorate of putrescine. 



(g) To a concentrated aqueous 

 solution add an alcoholic solution 

 of platinum chloride : crystalline 

 double salt. 



(h) Dissolve in hot water and 

 recrystallise. 



II. Pentamethylene-diamine 

 (cadaverine). 



(a) Dissolve crystals in a solu- 

 tion of equal volumes of alcohol 

 and concentrated hydrochloric acid. 



(6) Heat in water bath at 45 C. 

 for two days. 



(c) Dilute with water, till no 

 more precipitate appears. 



(d) Filter. 



(e) Filtrate shake with ether, 

 and separate the ethereal extract. 



(/) Slowly evaporate the ethereal 

 extract : crystalline mass, soluble 

 in water, not readily soluble in 

 alcohol = hydrochlorate of cada- 

 verine. 



(g) To a concentrated spirit 

 solution add an alcoholic solution 

 of platinum chloride : crystalline 

 double salt. 



(h) Dissolve in hot water and 

 recrystallise. 



Cultures of cholera and Finkler-Prior vibrios may be 

 examined for ptomaines in the same manner. 



