282 DR. KANE ON THE CHEMICAL HISTORY OF ARCHIL AND LITMUS. 
the fact. The difficulty might be got rid of, by supposing that the three lichens 
Roccella Tinctoria, Parmelia Roccella, and Lecanora Tart area, all contained primi- 
tively different characteristic bodies, which possessed the common character of 
generating his pseudo-erythrine, and the bodies which result from its decomposition ; 
but, although in a certain degree supported by the analogy of the Variolaria dealbata, 
which contains orcine and no erythrine, I consider this idea as being much less likely 
to be true, than that the erythrine of Heeren should be found to have been a mixture. 
It is on these grounds that I have transferred the name erythrine to his pseudo-ery- 
thrine, the substance which has been just now described. 
III. Of Erythrine-bitter . — Amarythrine. 
The substance which I shall now proceed to describe, is that which forms when 
erythrine is dissolved in hot water and exposed for some days to the action of the air. 
Its existence was recognised fully by Heeren, and I only propose the modification 
of his name as being in some degree more consonant to the principles of nomencla- 
ture in the English language. 
The amarythrine has a very peculiar bitter sweet taste, which, as well as its odour, 
resembles that of burned sugar. It is exceedingly soluble in water, much less 
so in alcohol, and not at all in ether. Its affinity for water is such, that it cannot be 
obtained in a solid form without partial decomposition. Exposed in vacuo over con- 
centrated sulphuric acid, it shows no tendency whatsoever to solidify, and remains 
in a stove at a temperature of 200° Fahr. for weeks perfectly liquid. If heated in an 
oil bath or over a lamp, the water may be expelled, but the brownish mass obtained 
is so evidently altered as to be unfit for analysis. 
The solution of amarythrine in water is of a pale brown colour, perfectly neutral 
to test paper. With the ordinary metallic salts it yields precipitates, which are, 
when dried, of a reddish brown colour. The constitution of these salts is perfectly 
definite, and hence by means of them the composition of the amarythrine may be com- 
pletely ascertained. The truly definite nature of the salts of amarythrine is fully 
shown by the fact, that the precipitate which first forms when a solution of nitrate of 
lead is precipitated by amarythrine, and the second portion which is produced when 
the acid supernatant liquor is neutralized by ammonia, were found to possess precisely 
the same composition. The amarythrate of lead was analysed as follows : 
A. 0*491 of the precipitate formed by amarythrine in a solution of nitrate of lead, the 
liquor being acid, gave 
0 208 of oxide of lead, and 0*015 of metallic lead. 
0 565 of the same substance gave 0*569 of carbonic acid, and 0*151 of water. 
B. 0*970 of the precipitate produced by neutralizing the acid liquor of A. gave 0*963 of 
carbonic acid, and 0*238 of water. 
T 122 of the same substance gave 0*237 of oxide of lead, and 0*260 of metallic lead. 
