258 CHEMISTRY OF THE PTOMAINS. 



melts at 229°-230°, and begins to sublime at 150°. It presents all 

 the characteristics of nicotinic acid, CgH^NOj, which is formed as 

 the result of oxidation of nicotin. With hydrochloric acid it forms 

 the compound CJH5NOJ.HCI. With copper acetate it forms a 

 salt ; this distilled with lime, yields a substance which on boiling 

 with platinum chlorid and water forms the compound (C5ll5NCl)j. 

 PtClj. This same substance forms an iodomethylate, which in al- 

 coholic solution gives, on addition of potash, the characteristic re- 

 action of pyridin bases. 



The base CjHjjN, therefore, yields pyridin and nicotinic acid. 



A Base, CgH,3N, was obtained by Grautier and Etard (1881) from 

 the chloroform extracts (see method, page 234) from putrefying 

 mackerel, as well as from the decomposing flesh of the horse and ox. 

 It is regarded by these authors as a constant and definite product of 

 the bacterial fermentation of albuminoid substances, but this view is 

 hardly justifiable, inasmuch as the base has not been found by other 

 investigators. It is accompanied by the base Cj^Hj^N^. Nencki 

 (1882) asserted the identity of this base with the one which he had 

 isolated in 1876, and to which he had ascribed the formula CjH,jN. 

 On the other hand, Gautier and Etard consider their base to be 

 identical with the hydrocoUidin obtained by Cahours and Etard by 

 the action of selenium on nicotin. 



An isomer of this base, hemopyrrol, has been prepared from hemin 

 and also from the chlorophyll derivative phyllocyanin. On oxida- 

 tion it yields urobilin (Nencki and Marchlewski, Ber. d. d. chem. 

 Ges., 34, 1687). 



The free base is an alkaline, almost colorless, oily liquid, pos- 

 sessing a penetrating odor resembling that of syringa. It is volatile 

 without decomposition, and boils at about 205°, while hydrocoUidin 

 boils at 210°. Its density at zero is 1.0296. When exposed to the 

 air it oxidizes slowly, becomes brown and viscous, and at the same 

 time absorbs carbonic acid. It differs from a collidin in possessing 

 a strong reducing action, since both the gold and platinum double 

 salts become reduced on heating, and even in the cold. 



The hydrochlorid, CjHjjN.HCl, is very soluble in water and in 

 alcohol, and usually forms fine needles resembling snow crystals. It 

 is neutral in reaction and possesses a bitter taste. In the presence 

 of an excess of acid it reddens and resinifies. 



The platinochlorid, (C8H,3N.HCl)jPtCl, (Pt = 29.7 per cent.), 

 is of a light-yellow, flesh color, crystalline, and but slightly soluble. 

 It dissolves on warming, and recrystallizes in bent needles. 



The aurochlorid is rather soluble, and becomes slowly reduced in 

 the cold ; rapidly on warming. 



This isomer of hydrocoUidin is strongly poisonous. Even so 

 small a dose as 0.0017 gram of the hydrochlorid produced, when in- 



