256 CHEMISTRY OF THE PTOMAINS. 



by the putrefaction of tyrosin, according to the following equation : 



CjHhNOs = CjHiiN + CO, + O. 



We know that tyrosin does split up, on being heated to 270°, into 

 carbonic acid and oxyphenyl-ethylamin, thus : 



xm. 

 C.H / = /OH 



\CH,.CHj.NH,.COOH QHZ + CO,. 



^CH,.CH,.NH, 



In 1883 Erlenmeyer and Lipp observed that phenyl-a-amido- 

 propionic acid (phenyl-alanin), on dry distillation, decomposed with 

 the formation, among other products, of a base having the composi- 

 tion CgHjjN. This base was found to be identical with phenyl- 

 ethylamin, CjHj.CHyCHj.NHjj, and in its properties and composition 

 it resembles Nencki's base. Later (1889), Nencki adopted a similar 

 view in regard to the nature of this base, and regarded it as possess- 

 ing the formula just given — ^that is phenyl-ethylamin. He con- 

 sidered phenyl amido-propionic acid — one of the three aromatic 

 nuclei contained in the albumin molecule — as the source of this base. 

 From the fact that phenyl-a-amido-propionic acid is a well-known 

 putrefactive product, it would seem that Nencki's base may arise 

 either by the putrefactive decomposition of that acid, or by the hyd- 

 rolytic cleavage of the acid as a consequence of the method employed 

 in isolating the base. The latter would seem to be the most prob- 

 able explanation of the genesis of this base, inasmuch as Brieger, by 

 using his method for the isolation of ptomains, was not able to ob- 

 tain it from putrid gelatin. 



The platinochlorid, (C8HnN.HCl)2PtCl^ (Pt = 29.89 per cent.), is 

 readily soluble in hot, and but slightly soluble in cold water, and 

 can be therefore recrystallized from water. It forms beautiful flat 

 needles. On dry heating it gives off an oil which possesses an odor 

 resembling very much that of xylol or cumol, and burns with a 

 smoky flame. This distinguishes Nencki's base from coUidin, since 

 the platinochlorid of the latter does not show this behavior. 



Nencki also obtained from putrid gelatin, under certain ill-defined 

 conditions, especially when no glycocoU was present, a basic product 

 which gave, with sulphuric acid, large lamellar crystals. The free 

 base forms a thick colorless syrup, possessing a nauseous, bitter taste. 

 It did not become crystalline even after standing some time. Unlike 

 the base CgH,jN, it is not volatile, and is, therefore, obtained on 

 evaporation of the acidulated solution after previous removal of the 

 volatile bases by distillation with baryta. 



A Base, CgHjjN, isomer of coUidin and of the preceding base, 

 with which it is possibly identical, was obtained by O. de Coninck 

 (1888) in the later stages of putrefaction of sea-polyps {^pmdpes 

 marins). It forms a yellowish, rather mobile liquid, possessing a 



