cirKMISTRY OF THE PTOMAINES. 209 



pyridinc bases. It absorbs earlwnie acid energetically from 

 the air, without losing thereby the repulsive odor. The 

 boiling-point of the 1'n-e base, MS ordinarily obtained, is 

 about l.'}~>. It is not decomposed by distillation with 

 pMta-^ium hydrate, and is rather dillieultly volatile with 

 steam. With acids it forms Ix'autiful crystalline salts. 

 Piitrcsrine unites with water, like ethylenediamine, to form 

 a hydrate, and this water can only be removal by distilla- 

 tion with metallic sodium. The perfectly anhydrous base 

 boils at 1 ."i(5-l ")7, and then solidifies to plates (BRlEGEli), 

 which melt at 24 (UDRANSZKY and BAUMANN). The 

 synthetic base boils at 158-160, and melts at 23- 

 24 (LADENHURG). Like cadaverine it is difficultly solu- 

 ble in ether. 



The constitution of putrcscine has been determined by 

 UDRANS/KY and BAUMANN (1888). They showed that 

 the diben/oyl compound of putrescine was identical with 

 that of the synthetic tetramethylenediamine and of the 

 l>a- which they found in the urine of cystinuria. 



Putreseine, therefore, is tetramethylenediamine, a homo- 

 lomie of eadaverine, and its rational formula is: 



CH.NH. 



The same authors (Zdtschr. f. Physiol. Chem. 13, 591) 

 point out that diamines may possibly occur in putrefaction 

 as the result of oxidation of nronamines. Tims, putrescine 

 mi^ht arise from methylamine according to the expiation : 



CH,.CH 2 .NH 2 CH 2 CII 2 NH 2 



+ 0=1 2 + H 2 0. 



CH S .CH 2 .NH 2 CII 2 CH 2 NH 3 



In a similar manner cadaverine mi^ht form from ethyl 

 and propylamine. 



Putrescine can be prepared synthetically, according to 

 LADENBURG'S method, by converting ethylene bromide into 

 the cyanide and then reducing this by means of sodium 

 in absolute alcohol. 



On heating the concentrated aqueous solution of the 

 hydrochloride with potassium nitrite there is produced an 



