366 
VEGETABLE ALKALOIDS. 
coal gas, but more aromatic, insoluble in water, and highly 
inflammable. To apply it an acid infusion of the barks or 
the vegetable is first made ; then potassa is added to render it 
alkaline ; after which one fourth its bulk of benzole is to be 
shaken with the solution, which takes up the alkaloid. The 
benzole is then to be distilled off. Modifications of this plan 
are resorted to for the different alkaloids, according to state- 
ments made by Mr. J. Williams. But by whatever process the 
separation may be effected, it is necessarily an operose 
one, and being so it becomes expensive, if the agent is 
required in an absolutely pure state ; while as yet it is an 
unsolved question in therapeutics, if it be desirable to remove 
the alkaloid from its natural combination with an acid before 
using it medicinally. There can be no questioning the fact 
that the principle thus obtained becomes freed from many ex- 
traneous matters, some of which are inert ; yet before it can 
really produce its effects, it has to be united to some acid, so as 
to render it again a soluble salt, or this change takes place in 
the stomach and intestines, which is necessarily at the expense 
of the vital force ; the pure alkaloids, as a class, being only par- 
tially soluble, as before remarked, and therefore not very 
active compounds, abstractedly considered. But is this com- 
bination always so desirable a one as that which nature 
furnishes us with? And does not the principle while being 
separated undergo some modification as to its action on the 
organism ? 
We have been led to ask these questions from perusing the 
article on Aloetine, or Aloine, by M. Robiquet, inserted, in 
our number for September last ; and at page 43 of the present 
volume will be found another paper on the same subject by 
Mr. T. B. Groves, both of whom question the purgative 
powers, per se, of this so-called active principle of aloes. 
Aloine may not, critically speaking, be one of the alkaloids, 
there being no nitrogen in its composition according to 
Robiquet, yet other chemists state the contrary. Still it is 
closely allied to them, for Meisner considers it to possess 
alkaline properties, and Winkler regards aloes itself as a 
neutral vegetable salt ; this substance being the base with 
which an acid is in union in the extract. On this account 
there have not been wanting those who, considering this to 
be the active principle in aloes, have thought that if it were 
separated from the resinous matter with which it is naturally 
combined, a more desirable purgative for the horse would be 
obtained ; that is, one less irritating in its action, and less 
likely to affect the urinary organs ; the full influence of the 
agent being then determined to the intestines, without any 
