Art. LIII.—On the Absorption of Certain Alkaloids by Aluminous Silicates.
[Read before the Wellington Philosophical Society, 23rd October, 1872.]
If an aqueous solution of strychnia is agitated a short time with common clay it will be found on testing the mixture that a part or the whole of the alkaloid (according to the quantity used) has been removed from solution and absorbed by the clay. The same effects follow when the clay is
previously calcined. Morphia and narcotina may be substituted for strychnia with like results, other alkaloids I have not tried. Those cited can be removed from the absorbent by acids. From the results of numerous experiments I find that of all the silicates cyanite and andalusite (pure silicates of alumina) are the most effective absorbents of such bodies.
The silicates of the alkaline earths, or alkalies simple or compounded either among themselves or with silicate of alumina, appear quite negative to the alkaloids named. Wavellite and anhydrous sesqui-oxide of iron had no absorbing power for them.
These results show that the portion of the clay concerned in the production of the phenomenon instanced is silicate of alumina, and I should conceive a double silicate* to be formed, in every case hydrous, the anhydrous silicates of alumina named passing completely to the hydrous condition when finely comminated and moistened with water as I have previously shown (Trans. N.Z. Inst., Vol. IV., p. 380).
[Footnote] * Since the communication of this paper I find that silica chemically prepared and rendered anhydrous by heat will also absorb strychnia from aqueous solution, clearly showing that at any rate single silicates of the alkaloids readily form.