100 
ON THE PURPLE FOXGLOVE. 
paste, which swelled, appearing to acquire a lighter tint from 
the interposition of gaseous bubbles. The temperature hav- 
ing been carried by degrees to 428°, the substance diminished 
in volume, re-acquiring the brown tint which it had at 392°. 
When tasted after this experiment, it had lost a great part of 
its bitterness, and had acquired an acid, astringent taste. 
Another portion, heated in the air on a slip of platina, be- 
came at first soft, then took fire and burnt briskly, but with a 
somewhat dull and smoky flame. No visible residue is left; 
but on moistening the spot with a little distilled water it be- 
comes alkaline. The same phenomenon has been observed to 
a certain extent upon burning a small quantity of perfectly 
pure crystallized morphine. If the digitaline is not in a pure 
state, it burns, forming a very high porous mass, which disap- 
pears entirely if calcination be continued. 
A portion burnt in a glass tube diffuses acid vapours. If it 
be heated with a fragment of potash, the vapours are alkaline ; 
but as this occurred when experimenting for comparison on 
some pure salicine, we considered that it was due to a pheno- 
menon similar to that described by MM. Faraday, Reiset and 
Gerhardt, and that the nitrogen here disengaged in the form of 
ammonia did not originate from the digitaline. 
We were desirous of verifying the presence or absence of 
nitrogen by M. Lassaigne's process, and experimented com- 
paratively on digitaline, salicine and morphine. In the first 
two cases we only obtained a faint greenish yellow tint, which 
we attributed to the persalt of iron, and with the morphine a 
slightly bluish emerald-green tint. Although these last results 
were not as decided as we had expected, for with morphine, a 
nitrogenous substance, we ought to have obtained a beautiful 
dark blue tint, yet as they were constantly the same in several 
experiments, w T e regarded them as confirmatory of our first 
conclusion, viz. that digitaline is not a nitrogenous compound. 
Cold water dissolves a little more than 1 -200th, boiling 
water about l-500th ; no opacity results on cooling. During 
