MYDIN. 287 



Mydin, CgHj^NO, is a non-poisonous base which was obtained by 

 Brieger in 1886 (III., 25) from the putrefaction of about two 

 hundred pounds of human internal organs ; and also in cultures of 

 the Eberth bacillus on peptonized blood-serum. It occurs in the 

 mercuric chlorid filtrate and is isolated, after the removal of the 

 mercury by hydrogen sulphid, by precipitation with phosphomo- 

 lybdic acid. The gummy precipitate which is produced is de- 

 composed on the water-bath with a solution of neutral lead acetate, 

 and the filtrate on evaporation yields a colorless hydrochlorid, crys- 

 tallizing in plates. It is purified by recrystallization of the picrate. 



The free base is strongly alkaline, and possesses an ammoniacal 

 odor. It is characterized by its strong reducing properties. The 

 name mydin is derived from (ioddw, to putrefy. With platinum 

 chlorid it gives, after a time, an extremely soluble salt ; with gold 

 chlorid, a precipitate of metallic gold. On distillation it is decom- 

 posed. 



The hydrochlorid, CjHj,NO.HCl, crystallizes in colorless plates. 

 It gives a blue color with ferric chlorid and potassium ferrocyanid. 



The picrate, CjHjjNO.C5H2(N02)30H, is obtained in broad prisms, 

 which melt at 195°. It is the only salt suitable for manipulations. 



In describing Nencki's coUidin (page 256) it was steted that 

 tyrosin might be looked upon as the source of that base. It would 

 seem, however, to be more appropriately the parent substance of 

 mydin, inasmuch as it decomposes on being heated to 270° into car- 

 bonic acid and oxyphenyl-ethylamin, CgHjjNO. The change that 

 takes place can be represented by the equation : 



.OH /OH 



c,h/ = C.h/ -I- CO,. 



\CH,.CHNH,.COjH ^CHj.CHj.NH^ 



Tyrosik. Oiyphknyl-ethylamin. 



A Base, C^HjiNOj, was isolated by E.and H. Salkowski (1883) 

 from decomposing fibrin and meat. An amino-valerianic acid is 

 formed in the hydrolytic cleavage by means of acids of the protamin 

 clupein (Kossel) ; and of casein (Fischer, 1901). The 5-acid also 

 results in the oxidation of piperidin {Ber., 25, 2778). For diamino- 

 valerianic acid, see ornithin. 



It is extremely soluble in water, very difficultly so in alcohol, in- 

 soluble in ether, and possesses a semen-like odor and saline taste. 

 The aqueous solution, which is not alkaline in reaction, yields on 

 evaporation a stellate crystalline mass which on standing over sul- 

 phuric acid becomes a white powder melting at 156°. It dis- 

 solves silver oxid but not cupric hydrate, thus apparently indicating 

 that it is not an amido acid. Moreover, it does not give a pre- 

 cipitate or blue coloration with copper acetate or ammoniacal silver 

 nitrate. It thus differed from the then known amido-valerianic acids, 

 its isomers. Later, however (1891), Grabriel and Aschan showed 



