ON ALOINj THE CATHARTIC PRINCIPLE OF THE ALOES. 275 
which was, at one time, agreed to for a settlement in this case, 
was not ultimately acceded to by the defender, and the large 
expense thereby avoided, which has been incurred by the con- 
sequent necessity of resorting to a court of law in order to de- 
termine the rights of parties. 
Home Extracts. 
ON ALOIN, THE CATHARTIC PRINCIPLE OF THE 
ALOES. 
By Messrs. H. & T. Smith, Chemists, Edinburgh. 
DURING last summer, having occasion to prepare a quantity 
of the aqueous extract of aloes — a preparation in repute with 
many medical men — we made use of cold rather than hot water 
as the solvent, from an impression that a more perfect, though 
less bulky, result would be obtained, by leaving in the marc a 
large proportion of resinous matter, which must necessarily be 
contained in the extract prepared from a hot solution. Further, 
with the view of rendering the preparation as perfect as pos- 
sible, the filtered liquid was evaporated in vacuo , — thereby 
avoiding an excess of heat, under the influence of which, and 
exposure to the air, recent researches shew the cathartic pro- 
perty of the aloes is seriously impaired. 
After the syrupy liquid had cooled, certain appearances ar- 
rested our attention, and seemed of sufficient importance to in- 
duce a departure from the original intention of forming it into 
a dry extract. The vessel containing the thin extract was now, 
therefore, set aside for a few days; and when again examined, 
the contents were found to have lost their original liquid state, 
and to have become loaded with a mass of granular crystalline 
matter. The whole was at once put into a cloth, and freed 
from the liquid portion by strong pressure. The crude solid 
substance left in the cloth being very impure, required further 
treatment before an opinion as to its nature could be formed, 
and was therefore dissolved in hot water, and filtered while still 
hot, out of contact with the air. On the cooling of the liquid, 
the substance separated in a crystalline state, and of a deep 
yellow colour. After a second pressure, it was subjected to 
another treatment, exactly like the last. The solid cake result- 
ing from the third pressure, after being completely dried, pre- 
