418 poisons : their effects and detection. [§ 500 . 
(C 15 H 21 N 3 0 2 HI,2HgI) is a white precipitate, insoluble in water, becoming 
yellow on drying, soluble in ether and alcohol, and from such solutions 
obtained in crystalline prismatic groups. A heat of 70° melts the crystals, 
and they solidify again in the amorphous condition. 
It gives a precipitate with gold chloride, reducing the gold ; also one 
with mercuric chloride, easily soluble in hydrochloric acid. It gives no 
precipitate with platinum chloride. 
§ 500. The constitution of eserine has been to a great extent un¬ 
ravelled by the researches of Petit and Polonovsky, 1 Ehrenberg, 2 and 
especially Salway. 3 These researches prove that the alkaloid contains 
the groups CO.NHMe, NMe, and NPh. Alkalies, in the absence of oxygen, 
produce an amino derivative (eseroline) of the complex C 13 H 16 ON, as 
represented by the equation, 
(C 13 H 18 ON)NH.CO.NHMe + H 2 0 = C 13 H ls ON.NH 2 + C0 2 +NH 2 Me. 
Or if eserine be considered a urethane, then the formula for 
eseroline is that of an alcohol, C 13 H 17 N 2 OH. Theoretically, therefore, 
100 parts of eserine would yield 79 of eseroline. Salway, operating on 
20 grms. of eserine dissolved in a little alcohol, with excess of solution 
of sodium hydroxide in a hydrogen atmosphere, at room temperature 
for four hours, and then extracting with ether, obtained from the 
ethereal extract 70 per cent, eseroline, which is not far from the 
calculated amount. 
Eseroline, C 13 H 18 ON 2 , m.p. 128°, may be obtained in white prisms. 
Specific rotatory power in methyl alcohol, [a] D —107-2°. It is readily 
soluble in alcohol, ether, chloroform, or benzene, but only slightly soluble 
in light petroleum. Salway crystallised it from a mixture of benzene 
and petroleum. The free base is quite stable when pure, but in neutral 
or acid solutions it is slowly oxidised; in alkaline solutions the oxidation 
is very rapid. From its easy oxidation it strongly reduces silver nitrate 
and the chlorides of gold and platinum. It possesses feeble acidic 
properties, and is easily soluble in alkaline hydroxides, from whence, in 
the absence of oxygen, it may be recovered unchanged. Eseroline 
hydrochloride, C 13 H 18 0N 2 HC1, prepared by passing dry HC1 gas into an 
ethereal solution of the base, maybe obtained in stellate clusters of needles, 
m.p. 212°. The picrate melts at 195°. By allowing an alkaline solution 
to absorb oxygen in the proportion of 2 atoms to the molecule, a red sub¬ 
stance is produced— Rubreserine. The successive steps in the formation 
of rubreserine occur according to the following scheme :— 
KOH 0 2 
Eserine -> Eseroline Rubreserine. 
^i 5 H 2 i^ 2^3 C 13 H 18 ON 2 C 13 H 16 0 2 N 2 
1 Bull. Soc. Chun., 1893. 2 Ver. Ges. Deut. Naturforsch. Aerzte, 1893. 
3 Journ. Chem. Soc., T., 1912. 
