ON SOME VEGETABLE ALKALOIDS. 29 
I shall shew presently, from an analysis and description of the base obtained 
from this salt, that there can be no doubt of its real nature; so that, under these 
circumstances, papaverine behaves in a manner similar to that shewn before* to 
be the case when hydrated morphia is placed in contact with chloride of amyl, it 
forms a salt, namely, with the halogen of the ether compound, while no doubt the 
corresponding alcohol is simultaneously generated by the agency of the elements 
of water, as in the equation— 
C,, H,, NO,+C, H, 1+2HO=C,, H,, NO, HI+C, H, 0, ; 
this, at least, seems the most obvious explanation of the change when water is 
present. To determine if the formation of the salt were really due to the agency 
of water, I repeated the experiment with absolute alcohol in place of rectified 
spirit, and the papaverine was dried at 212°, to remove accidental moisture, its 
crystals containing no water of combination. In this case, also, the hydriodate 
was formed from part of the alkaloid, the rest remaining unaltered. The iodide 
of ethyl had been distilled from chloride of calcium, and I should think could 
furnish, at the most, but a minute quantity of water ; and it is not easy to see how 
the reaction is brought about under these circumstances, unless it be assumed 
that it occurs with the formation of ether. The detection of this substance would 
not be readily effected upon the small scale upon which I worked, and I there- 
fore only throw out the following equation as a possible explanation of the re- 
action— 
C,, H,, NO,+C, H, 1+C, H, 0,=C,, H,, NO, HI+2 C, H, 0. 
As no account has yet been given of the hydriodate of papaverine, a short 
description of it may be subjoined. The salt is extremely soluble in boiling 
water, and the moment the heat ‘is withdrawn from a strong solution, the fiuid 
assumes a milky appearance, and an oil is soon deposited, which, after some 
hours, passes into the form of stellate colourless needles; it is also soluble in 
spirits of wine, but in absolute alcohol it dissolves with far less facility, and it re- 
quires protracted boiling, when the salt has once taken on the crystalline condi- 
tion, to obtain perfect solution with this menstruum. The hot liquid deposits the 
salt rapidly, as it cools, in colourless rhombic crystals. When exposed to a tem- 
perature of 212° Fahrenheit, in a dry state, the hydriodate of papaverine assumes 
a brown tint, loses slightly in weight, and is found to have undergone some de- 
composition, as it no longer dissolves completely in hot water, but leaves a brown 
resinous matter. 
By addition of ammonia to the mother liquors of the salt which had been 
analysed, a white crystalline precipitate was obtained; this was recrystallized 
from dilute spirit, and burnt with chromate of lead :— 
* Quart. Journ. Chem. Soc., vol. vi. 
