PUTBESCIN. 269 



liver (Scherer); in beef kidneys (Cloetta); in decomposing pancreas 

 (Kiilz); in the liver of a horse and a dolphin (Dreschel), and in a 

 tyrosin preparation from horn (Emmerling). The studies of Baumann 

 and of Dreschel led these investigators to regard cystin as a normal 

 intermediate waste-product, but no definite evidence of this was 

 brought out until Morner (1899) succeeded for the first time in pre- 

 paring cystin by the hydrolysis of horn (6.8 per cent.), egg-mem- 

 brane (6 per cent.), and human hair (12.6 per cent.). Embden 

 (1901) obtained it in like manner from serum and egg-albumin. 

 Moreover, both confirmed Kiilz's observation as to the formation of 

 cystin in tryptic digestion. Apparently all proteids which contain 

 sulphur in a form which can easily be split off contain the cystin 

 group. This fact, considered in connection with the now known 

 source of the diamins, renders it evident that cystinuria is due to a 

 condition of abnormal tissue metabolism rather than to a peculiar 

 intestinal decomposition. The presence of diamins in the intestine 

 is probably due to an elimination. 



Putrescin can be prepared synthetically, according to Ladenburg's 

 method, by converting ethylene bromid into the cyanid and then 

 reducing this by means of sodium in absolute alcohol. It is an 

 isomer of Angeli's dimethylethylenediamin. 



On heating the concentrated aqueous solution of the hydrochlorid 

 with potassium nitrite there is produced an oil, soluble in water, 

 from which it can be extracted with ether. This oil, on treatment 

 with phenol and sulphuric acid, gives Liebermann's nitroso-reaction, 

 which would seem to show that putrescin is not a primary diamin 

 (butylenediamin), but is rather a secondary diamin (Brieger, II., 42). 

 As a primary diamin it should take up, on repeated treatment with 

 methyl iodid, six methyl radicals ; whereas, if it is a secondary dia- 

 min, only four methyl radicals can enter the molecule. Thus, to 

 illustrate, methy lamin, CHg.NHj (a primary amin), combines with 

 three molecules of methyl iodid to form (CH3)^N.HI. Similarly, 

 dimethylamin, (CHj)^.!^!!, requires only two molecules to form 

 (CH3)^N.HI. In the case of diamins, double this number of methyl 

 groups is required to effect complete saturation. As a matter of fact, 

 Brieger (III., 101), on treating putrescin with methyl iodid, suc- 

 ceeded in introducing four, and only four, methyl radicals. From 

 this, however, it does not follow that putrescin is not a primary amin, 

 since cadaverin, an unquestioned primary diamin, yields a substitu- 

 tion compound containing only two methyl groups (see p. 274). 



The tetra-methyl substitution product of putrescin, C^Hg(CH3)^]Sr2, 

 can be distilled without decomposition. The free base crystallizes 

 in long prisms. The hydrochlorid forms small needles which are 

 easily soluble ; with phosphotungstic acid it gives a white crystalline 

 precipitate, with phosphomolybdic acid a yellow crystalline precip- 

 itate, with picric acid needles. Potassium bismuth iodid gives a 



