43 
ALOINE. 
By Mr. T. B. Groves. 
In tlie July, 1851, number of the Pharmaceutical Journal , appeared a 
paper by Messrs. Smith, of Edinburgh, on Aloine, a crystalline principle they 
had succeeded in isolating from Barbadoes aloes, and which they regarded as 
its active principle. They proved also the existence of this body in a crys- 
talline state in the Cape and Socotrine varieties, though they succeeded in 
obtaining from them only very insignificant quantities. 
The behaviour of aloine with reagents was fully detailed by them, and its 
formula supplied, as obtained by Dr. Stenhouse. 
This latter chemist also devoted considerable attention to the subject, and 
arrived at the same results as Messrs. Smith — that aloine is scarcely obtain- 
able in sufficient quautity, or in such a state of purity as to be recognisable, 
from any other than the Barbadoes variety. 
M. Robiquet, in an article read to the Academie de Medecine,* February 
26, 1856, and published in the Chemist of July, 1856, arrived at the same 
conclusion with regard to Cape and Socotrine aloes, but gives a much more 
easy and productive process for its preparation from Barbadoes aloes. 
All these gentlemen express their belief that the opaque varieties alone 
contain any considerable proportion of aloine in a crystallizable state, and 
that the vitreous or translucent varieties have undergone the action of heat 
subsequent to inspissation, and that the fusion has converted the aloine into 
an amorphous substance, quasi-resinous. From a perusal of the works of 
the first two experimenters, and a consideration of what had hitherto been 
published respecting the manufacture of the different varieties of aloes, I was 
early led to doubt the accuracy of some of their conclusions. 
For instance, Pereira states that the best Barbadoes aloes is procured by 
evaporating in a copper vessel, over a naked fire, the juice that spontaneously 
exudes from the transversely cut stems of the aloe (the decoction of the leaves 
is not unfrequently used), and that the evaporation is carried to such a 
point that the extract on cooling “ breaks short ” — in other words, has been 
reduced to dryness and incipient fusion. 
The Socotrine, on the contrary, appears to be the pure spontaneously 
exuded juice of the cut leaves, evaporated, after depositing its grosser parts, 
by the sole agency of the sun. 
If it be true then that aloine is so readily altered by contact of air, simul- 
taneously with the application of heat, one would scarcely be justified in 
attempting its preparation from the former kind, without first applying to 
the latter. 
Again, aloine is proved to be but slightly soluble in cold water ; then why 
use cold for its separation ? or ether, which dissolves it so sparingly ? 
I shall be able to show that Socotrine aloes contains a considerable pro- 
portion of crystallizable aloine, to be obtained from it without extraordinary 
difficulty or precaution. 
The following circumstance that occurred shortly after the publication of 
Messrs. Smith’s paper, first suggested an inquiry. I was engaged in filling 
a small pot with the aqueous extract of Socotrine aloes, when 1 was called 
away for a short time, and on returning, observed that a bubble of con- 
siderable size had, by the gradual subsidence of the extract, formed on its 
surface. The extract, when first made, had been perfectly transparent, but 
the surface of the bubble I observed to be studded with bodies of a regular 
* Given in our number for September. 
