PUTBESCIN. 267 



solved in just sufficient warm alcohol to effect solution, and this is 

 then poured into about twenty times its volume of ether. The 

 putrescin benzoyl compound is thus thrown out of solution. The 

 filtrate from this, on concentration, yields the cadaverin compound. 

 To isolate that portion of the diamins which remains in the original 

 filtrate with benzoyl-cystin, it is acidulated with sulphuric 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 diamins. 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 diamins insoluble. To purify the benzoyl- 

 diamins they are dissolved in warm alcohol and precipitated with 

 excess of water. 



Putrescin (from putrescere, to rot, to putrefy) is a water-clear, rather 

 thin liquid which fumes in the air and has a peculiar semen-like 

 odor, almost undistinguishable from that of cadaverin and remind- 

 ing one somewhat of the pyridin bases. It absorbs carbonic acid 

 energetically from the air, without losing thereby the repulsive odor. 

 The boiling point of the free base, as ordinarily obtained, is about 

 135°. It is not decomposed by distillation with potassium hydrate, 

 and is rather difficultly volatile with steam. With acids it forms 

 beautiful crystalline salts. Putrescin unites with water, like ethyl- 

 enediamin, to form a hydrate, and this water can only be removed 

 by distillation over metallic sodium. The perfectly anhydrous base 

 boils at 156°— 157°, and then solidifies to plates (Brieger), which 

 melt at 24° (Udrfinszky and Baumann). The synthetic base boils 

 at 158°-160°, and melts at 23°-24° (Ladenburg). Like cadaverin 

 it is difficultly soluble in ether. 



The constitution of putrescin has been determined by Udrinszky 

 and Baumann (1888). They showed that the dibenzoyl compound 

 of putrescin was identical with that of the synthetic tetramethylene 

 diamin and of the base which they found in the urine of cystinuria. 



Putrescin, therefore, is tetramethylenediamin, a homologue of 

 cadaverin, and its rational formula is : 



NH,. CHj. CHj. CH,. CH,. NH,. 



The same authors {ZeUsahr. f. physiol. Chem., 13, 591) pointed 

 out that diamins might possibly occur in putrefaction as the result 

 of oxidation of monamins. Thus, putrescin might arise from methyl- 

 amin according to the equation : 



CHs.CH,.NHj CHs.CHj.NH5 



4-0= I +H,0. 



CHj-CHi.NH, CHj.CHj NHj 



